Academic literature on the topic 'Continuous energy restriction obesity'

The current obesity epidemic is staggering in terms of its magnitude and public health impact. Current guidelines recommend continuous energy restriction (CER) along with a comprehensive lifestyle intervention as the cornerstone of obesity treatment, yet this approach produces modest weight loss on average. Recently, there has been increased interest in identifying alternative dietary weight loss strategies that involve restricting energy intake to certain periods of the day or prolonging the fasting interval between meals (i.e., intermittent energy restriction, IER). These strategies include intermittent fasting (IMF; >60% energy restriction on 2–3 days per week, or on alternate days) and time-restricted feeding (TRF; limiting the daily period of food intake to 8–10 h or less on most days of the week). Here, we summarize the current evidence for IER regimens as treatments for overweight and obesity. Specifically, we review randomized trials of ≥8 weeks in duration performed in adults with overweight or obesity (BMI ≥ 25 kg/m2) in which an IER paradigm (IMF or TRF) was compared to CER, with the primary outcome being weight loss. Overall, the available evidence suggests that IER paradigms produce equivalent weight loss when compared to CER, with 9 out of 11 studies reviewed showing no differences between groups in weight or body fat loss.

Recently, intermittent fasting has gained relevance as a strategy to lose weight and improve health as an alternative to continuous caloric restriction. However, the metabolic impact and the sex-related differences are not fully understood. The study aimed to compare the response to a continuous or intermittent caloric restriction in male and female rats following a previous induction of obesity through a cafeteria diet by assessing changes in body weight, energy intake, metabolic parameters, and gene expression in liver hepatic and adipose tissue. The continuous restriction reduced the energy available by 30% and the intermittent restriction consisted of a 75% energy reduction on two non-consecutive days per week. The interventions reduced body weight and body fat in both sexes, but the loss of WAT in females was more marked in both models of caloric restriction, continuous and intermittent. Both caloric restrictions improved insulin sensitivity, but more markedly in females, which showed a more pronounced decrease in HOMA-IR score and an upregulation of hepatic IRS2 and Sirt1 gene expression that was not observed in males. These findings suggest the fact that females are more sensitive than males to reduced caloric content in the diet.

An alternative to continuous energy restriction in the medical nutrition treatment of obesity, which has come to the fore in recent times, is called intermittent fasting. The aim of this study is to compare the effects of intermittent energy restriction (IER) and continuous energy restriction (CER) practices on body composition and anthropometric measurements in overweight and first-degree obese individuals. The comparison study was conducted on 34 people aged 19-64 between April and September 2022. They had no health problems, and applied to a private institution providing nutrition consultancy. In the study, the participants were divided into two groups and were asked to maintain the IER or CER diet type for six weeks. When the participants in the two diet types were compared in terms of parameters of anthropometric measurements, body compositions, blood pressure measurements, and initial and final measurements of abdominal fat analysis, no statistically significant difference was found (pα, pβ>0.05). The mean weight loss of the participants in the IER and CER groups was 3.95±1.94 kg and 4.09±1.48 kg, respectively. The weight loss of the participants in the two diet groups was similar. The long-term efficacy and safety of time-restricted feeding in weight loss is still unclear. More comprehensive research is needed on this subject.

An alternative to continuous energy restriction in the medical nutrition treatment of obesity, which has come to the fore in recent times, is called intermittent fasting. The aim of this study is to compare the effects of intermittent energy restriction (IER) and continuous energy restriction (CER) practices on body composition and anthropometric measurements in overweight and first-degree obese individuals. The comparison study was conducted on 34 people aged 19-64 between April and September 2022. They had no health problems, and applied to a private institution providing nutrition consultancy. In the study, the participants were divided into two groups and were asked to maintain the IER or CER diet type for six weeks. When the participants in the two diet types were compared in terms of parameters of anthropometric measurements, body compositions, blood pressure measurements, and initial and final measurements of abdominal fat analysis, no statistically significant difference was found (pα, pβ>0.05). The mean weight loss of the participants in the IER and CER groups was 3.95±1.94 kg and 4.09±1.48 kg, respectively. The weight loss of the participants in the two diet groups was similar. The long-term efficacy and safety of time-restricted feeding in weight loss is still unclear. More comprehensive research is needed on this subject.

Fibroblast growth factor-21 (FGF-21), is a protein involved in cell growth and differentiation, development, wound repair and metabolism. Research looking at the impact of weight loss on FGF-21 levels is limited. The objective of this exploratory study was to determine changes in serum FGF-21 levels following weight loss induced by either continuous energy restriction or intermittent energy restriction. A sub cohort of participants who completed a 12-month dietary intervention trial following continuous energy restriction, or a week-on week-off energy restriction pattern, were selected for analysis. FGF-21 levels were not altered by weight loss and were not correlated with body weight or BMI at baseline or 12 months. Weight loss after 12 months either through continuous energy restriction or intermittent energy restriction was −5.9 ± 4.5 and −4.9 ± 3.4 kg, respectively. There was no change in FGF-21 levels, 0.3 ± 0.9 and 0.04 ± 0.2 ng/mL (p = 0.2). In conclusion, weight loss in healthy overweight or obesity subjects did not affect FGF-21 levels.

There is considerable heterogeneity across the evidence regarding the effects of intermittent energy restriction and continuous energy restriction among adults with overweight or obesity which presents difficulties for healthcare decision-makers and individuals. This overview of systematic reviews aimed to evaluate and synthesize the existing evidence regarding the comparison of the two interventions. We conducted a search strategy in eight databases from the databases’ inception to December 2021. The quality of 12 systematic reviews was assessed with A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) and the Grading of Recommendations Assessment, Development and Evaluation (GRADE). One review was rated as high quality, 1 as moderate, 4 as low, and 6 as critically low. A meta-analysis of the original studies was conducted for comparison of primary intermittent energy restriction protocols with continuous energy restriction. Intermittent energy restriction did not seem to be more effective in weight loss compared with continuous energy restriction. The advantages of intermittent energy restriction in reducing BMI and waist circumference and improvement of body composition were not determined due to insufficient evidence. The evidence quality of systematic reviews and original trials remains to be improved in future studies.

Obesity in the United States and Western countries represents a major health challenge associated with an increased risk of metabolic diseases, including cardiovascular disease, hypertension, diabetes, and certain cancers. Our past work revealed a more pronounced obesity–cancer link in certain ethnic groups, motivating us to develop a tailored dietary intervention called the Healthy Diet and Lifestyle 2 (HDLS2). The study protocol is described herein for this randomized six-month trial examining the effects of intermittent energy restriction (5:2 Diet) plus the Mediterranean dietary pattern (IER + MED) on visceral adipose tissue (VAT), liver fat, and metabolic biomarkers, compared to a standard MED with daily energy restriction (DER + MED), in a diverse participant group. Using MRI and DXA scans for body composition analysis, as well as metabolic profiling, this research aims to contribute to nutritional guidelines and strategies for visceral obesity reduction. The potential benefits of IER + MED, particularly regarding VAT reduction and metabolic health improvement, could be pivotal in mitigating the obesity epidemic and its metabolic sequelae. The ongoing study will provide essential insights into the efficacy of these energy restriction approaches across varied racial/ethnic backgrounds, addressing an urgent need in nutrition and metabolic health research. Registered Trial, National Institutes of Health, ClinicalTrials.gov (NCT05132686).

Background Adaptive thermogenesis, defined as the decrease in the energy expenditure components beyond what can be predicted by changes in body mass stores, has been studied as a possible barrier to weight loss and weight maintenance. Intermittent energy restriction (IER), using energy balance refeeds, has been pointed out as a viable strategy to reduce adaptive thermogenesis and improve weight loss efficiency (greater weight loss per unit of energy deficit), as an alternative to a continuous energy restriction (CER). Following a randomized clinical trial design, the BREAK Study aims to compare the effects of IER versus CER on body composition and in adaptive thermogenesis, and understand whether participants will successfully maintain their weight loss after 12 months. Methods Seventy-four women with obesity and inactive (20–45 y) will be randomized to 16 weeks of CER or IER (8x2 weeks of energy restriction interspersed with 7x1 week in energy balance). Both groups will start with 2 weeks in energy balance before energy restriction, followed by 16 weeks in energy restriction, then 8 weeks in energy balance and finally a 12-month weight maintenance phase. Primary outcomes are changes in fat-mass and adaptive thermogenesis after weight loss and weight maintenance. Secondary outcomes include weight loss, fat-free mass preservation, alterations in energy expenditure components, and changes in hormones (thyroid function, insulin, leptin, and cortisol). Discussion We anticipate that The BREAK Study will allow us to better understand adaptive thermogenesis during weight loss and weight maintenance, in women with obesity. These findings will enable evidence-based decisions for obesity treatment. Trial registration ClinicalTrials.gov: NCT05184361.

The purpose of this study is to present the results of a comparative assessment of the effect of intermittent restricted diet (ICR) with a constant restricted diet (CCR) on weight loss, fat mass, the effect on cardiometabolic risk markers, glucose and insulin levels in obese adults. Materials and methods: The works cited in the study were selected using the keywords “obesity”, “comorbidity”, “weight loss”, “intermittent calorie restriction”, “constant calorie restriction”, in the search engines PubMed, Scopus. Publications had to meet the following criteria: randomized clinical trials, published in the last decade (2014-2024), access to the full text of the publication, the primary endpoint of weight loss, intermittent or continuous calorie restriction as the main intervention, adult population, subjects with obesity and comorbid pathology. Results: Obesity has acquired pandemic proportions worldwide. In some countries, prevalence rates range from 20 to 40%. Prevalence and incidence rates continue to increase. It is estimated that by 2030, almost 50% of the world’s population will be overweight or obese. Obesity increases the risk of a number of chronic noncommunicable diseases (T2DM, CVD, CKD, CLD, some types of cancer). Weight loss is the main intervention for people with overweight and obesity. Conservative non-drug therapy in the form of nutritional modification is the mainstay of obesity treatment and is recommended as the first, mandatory and permanent component of treatment. Daily caloric restriction and intermittent feeding are two forms of dietary therapy that can help to reduce body weight. Conclusion: Based on the results of the comparative analysis, we concluded that ICR and CCR are alternative energy restriction regimens for weight loss with comparable improvements in obesity-related cardiometabolic risk markers. Both regimens were well tolerated in most studies and may be equivalent approaches to weight loss. Further studies are needed to examine the efficacy, feasibility and safety of ICR in patients with chronic diseases such as type 2 diabetes, cardiovascular disease or cancer.

This thesis consists of two literature reviews followed by three empirical chapters that examined the relationship between chronic sleep restriction and obesity. Chapter 2 reviewed available research data and presented a theoretical model linking chronic sleep restriction to obesity. This model hypothesises that chronic sleep restriction contributes to obesity by altering energy regulatory hormones such as ghrelin and leptin. It was also argued that factors such as poor mental health, medication use and long work hours contribute to chronic sleep restriction at a population level, and could have implications for improving sleep. This model provides a sound theoretical framework, which was used to guide the subsequent empirical chapters. In chapter 3, the key methodological limitations of previous studies examining the relationship between chronic sleep restriction and obesity were outlined. Methodological recommendations for future research were then provided to facilitate a more complete understanding of how chronic sleep restriction and obesity are linked in the general population. Chapter 4 tested a path model linking chronic sleep restriction to obesity in 325 adults aged 18 to 87 years, based on the theoretical framework provided in chapter 2 and the methodological recommendations listed in chapter 3. The results indicated that short sleep durations and age were associated with obesity, whilst age, uncomfortable sleep environments, irregular sleep/wake cycles and poor mental health were associated with short sleep durations. However, the results also identified potential environmental, behavioural and psychological determinants of chronic sleep restriction that could be targeted in the future treatment and prevention of obesity. Chapter 5 examined the relationship between three dimensions of sleep quality as assessed by the Pittsburgh Sleep Quality Index and obesity in 262 adults aged 18 to 35 years. Short sleep durations and increased levels of daytime dysfunction (e.g., sleepiness) were associated with obesity, whilst irregular bedtimes, noisy environments, discomfort and depression were the major factors associated with poor sleep quality. These factors could play a role in obesity interventions that target sleeping patterns and need to be further investigated. Finally, chapter 6 examined the effects of two nights of seep restriction on energy expenditure and neuroendocrine hormones involved in energy balance regulation in ten healthy male adults. The results indicated that sleep restriction led to an increase in ghrelin and a reduction in PYY, which corresponded with increased hunger and reduced satiety. The results also suggested that energy expenditure declined with sleep restriction. These results suggest that sleep restriction could contribute to obesity by altering energy expenditure and the hormonal regulation of food intake. The findings from this thesis therefore suggest that chronic sleep restriction contributes to the development of obesity by altering key pathways identified in chapter 2. The identification of possible determinants of chronic sleep restriction has potential applications for the treatment and prevention of obesity. For example, the factors identified in chapters 4 and 5 could be targeted as a way to promote healthy sleep durations, and could be effective in improving the efficacy of existing interventions for obesity.

Previous studies have shown that exercise (Ex) interventions create a stronger coupling between energy intake (EI) and energy expenditure (EE) leading to increased homeostasis of the energy-balance (EB) regulatory system compared to a diet intervention where an un-coupling between EI and EE occurs. The benefits of weight loss from Ex and diet interventions greatly depend on compensatory responses. The present study investigated an 8-week medium-term Ex and diet intervention program (Ex intervention comprised of 500kcal EE five days per week over four weeks at 65-75% maximal heart rate, whereas the diet intervention comprised of a 500kcal decrease in EI five days per week over four weeks) and its effects on compensatory responses and appetite regulation among healthy individuals using a between- and within-subjects design. Effects of an acute dietary manipulation on appetite and compensatory behaviours and whether a diet and/or Ex intervention pre-disposes individuals to disturbances in EB homeostasis were tested. Energy intake at an ad libitum lunch test meal after a breakfast high- and low-energy pre-load (the high energy pre-load contained 556kcal and the low energy pre-load contained 239kcal) were measured at the Baseline (Weeks -4 to 0) and Intervention (Weeks 0 to 4) phases in 13 healthy volunteers (three males and ten females; mean age 35 years [sd + 9] and mean BMI 25 kg/m2 [sd + 3.8]) [participants in each group included Ex=7, diet=5 (one female in the diet group dropped out midway), thus, 12 participants completed the study]. At Weeks -4, 0 and 4, visual analogue scales (VAS) were used to assess hunger and satiety and liking and wanting (L&W) for nutrient and taste preferences using a computer-based system (E-Prime v1.1.4). Ad libitum test meal EI was consistently lower after the HE pre-load compared to the LE pre-load. However, this was not consistent during the diet intervention however. A pre-load x group interaction on ad libitum test meal EI revealed that during the intervention phase the Ex group showed an improved sensitivity to detect the energy content between the two pre-loads and improved compensation for the ad libitum test meal whereas the diet group’s ability to differentiate between the two pre-loads decreased and showed poorer compensation (F[1,10]=2.88, p-value not significant). This study supports previous findings of the effect Ex and diet interventions have on appetite and compensatory responses; Ex increases and diet decreases energy balance sensitivity.

Two thirds of American adults are overweight and almost half of those qualify as obese. Obesity independently increases risk for cardiovascular disease (CVD), type II diabetes (T2D), and hypertension; thus, strategies to reduce risk in this population are desperately needed. Oxidative stress and inflammation are two perpetuators of these chronic diseases that are often elevated in obesity. Interventions that target reductions in oxidative stress and inflammation may help to reduce co-morbidities associated with obesity. Weight loss is shown to reduce oxidative stress and inflammation. However, the composition of and food choices within the weight loss diet may influence the response of these factors to weight loss, and has not been adequately assessed. We first tested whether there were differential effects of a conventional low-fat, high carbohydrate weight loss diet (LF) and the Atkins diet (a popular low carbohydrate, high fat diet (HF)) on oxidative stress and inflammation. We demonstrated that HF raised C-reactive protein (CRP) levels relative to LF in overweight and obese women over four weeks. This finding raises questions as to the long term safety of the HF eating plan in terms of CVD risk. We next examined the role of oxidative stress in the HF diet-induced increase in inflammation by evaluating the effects of an antioxidant supplement versus a placebo in conjunction with HF in overweight and obese men and women. Although our full hypothesis was not supported, as oxidative stress did not increase with HF, the trend for a differential effect on CRP when antioxidants were consumed is provocative. It suggests that future research on the connection between oxidative stress, the macronutrient content of the diet, and inflammation in obesity is warranted. Regarding the effects of specific fats, epidemiological research shows that diets high in saturated fat (SFA) are associated with higher CVD risk while diets higher in omega 3 fats (n-3FA) with lower CVD risk. However, the acute effects of these fats on indices of inflammation and oxidative stress are less understood, particularly in the overweight/obese population. As the majority of the time is spent in the postprandial state, the acute responses to high fat meals are gaining attention for their contribution to endothelial dysfunction and CVD. We showed that acute meals high in SFA increased a marker of endothelial activation (ICAM-1) which could contribute to the atherogenic associations with SFA. Conversely, including n-3FA in a high fat meal acutely enhanced NF-κB activation in circulating mononuclear cells; however, there were no increases in any inflammatory proteins measured over the 6 h postprandial period. It is apparent that dietary macronutrients can influence factors associated with chronic disease in overweight and obese individuals. The evidence presented here may help to refine dietary recommendations for this population.<br>Ph. D.

Diet Induced Thermogenesis (DIT) is the energy expended consequent to meal consumption, and reflects the energy required for the processing and digestion of food consumed throughout each day. Although DIT is the total energy expended across a day in digestive processes to a number of meals, most studies measure thermogenesis in response to a single meal (Meal Induced Thermogenesis: MIT) as a representation of an individual’s thermogenic response to acute food ingestion. As a component of energy expenditure, DIT may have a contributing role in weight gain and weight loss. While the evidence is inconsistent, research has tended to reveal a suppressed MIT response in obese compared to lean individuals, which identifies individuals with an efficient storage of food energy, hence a greater tendency for weight gain. Appetite is another factor regulating body weight through its influence on energy intake. Preliminary research has shown a potential link between MIT and postprandial appetite as both are responses to food ingestion and have a similar response dependent upon the macronutrient content of food. There is a growing interest in understanding how both MIT and appetite are modified with changes in diet, activity levels and body size. However, the findings from MIT research have been highly inconsistent, potentially due to the vastly divergent protocols used for its measurement. Therefore, the main theme of this thesis was firstly, to address some of the methodological issues associated with measuring MIT. Additionally this thesis aimed to measure postprandial appetite simultaneously to MIT to test for any relationships between these meal-induced variables and to assess changes that occur in MIT and postprandial appetite during periods of energy restriction (ER) and following weight loss. Two separate studies were conducted to achieve these aims. Based on the increasing prevalence of obesity, it is important to develop accurate methodologies for measuring the components potentially contributing to its development and to understand the variability within these variables. Therefore, the aim of Study One was to establish a protocol for measuring the thermogenic response to a single test meal (MIT), as a representation of DIT across a day. This was done by determining the reproducibility of MIT with a continuous measurement protocol and determining the effect of measurement duration. The benefit of a fixed resting metabolic rate (RMR), which is a single measure of RMR used to calculate each subsequent measure of MIT, compared to separate baseline RMRs, which are separate measures of RMR measured immediately prior to each MIT test meal to calculate each measure of MIT, was also assessed to determine the method with greater reproducibility. Subsidiary aims were to measure postprandial appetite simultaneously to MIT, to determine its reproducibility between days and to assess potential relationships between these two variables. Ten healthy individuals (5 males, 5 females, age = 30.2 ± 7.6 years, BMI = 22.3 ± 1.9 kg/m2, %Fat Mass = 27.6 ± 5.9%) undertook three testing sessions within a 1-4 week time period. During the first visit, participants had their body composition measured using DXA for descriptive purposes, then had an initial 30-minute measure of RMR to familiarise them with the testing and to be used as a fixed baseline for calculating MIT. During the second and third testing sessions, MIT was measured. Measures of RMR and MIT were undertaken using a metabolic cart with a ventilated hood to measure energy expenditure via indirect calorimetry with participants in a semi-reclined position. The procedure on each MIT test day was: 1) a baseline RMR measured for 30 minutes, 2) a 15-minute break in the measure to consume a standard 576 kcal breakfast (54.3% CHO, 14.3% PRO, 31.4% FAT), comprising muesli, milk toast, butter, jam and juice, and 3) six hours of measuring MIT with two, ten-minute breaks at 3 and 4.5 hours for participants to visit the bathroom. On the MIT test days, pre and post breakfast then at 45-minute intervals, participants rated their subjective appetite, alertness and comfort on visual analogue scales (VAS). Prior to each test, participants were required to be fasted for 12 hours, and have undertaken no high intensity physical activity for the previous 48 hours. Despite no significant group changes in the MIT response between days, individual variability was high with an average between-day CV of 33%, which was not significantly improved by the use of a fixed RMR to 31%. The 95% limits of agreements which ranged from 9.9% of energy intake (%EI) to -10.7%EI with the baseline RMRs and between 9.6%EI to -12.4%EI with the fixed RMR, indicated very large changes relative to the size of the average MIT response (MIT 1: 8.4%EI, 13.3%EI; MIT 2: 8.8%EI, 14.7%EI; baseline and fixed RMRs respectively). After just three hours, the between-day CV with the baseline RMR was 26%, which may indicate an enhanced MIT reproducibility with shorter measurement durations. On average, 76, 89, and 96% of the six-hour MIT response was completed within three, four and five hours, respectively. Strong correlations were found between MIT at each of these time points and the total six-hour MIT (range for correlations r = 0.990 to 0.998; P < 0.01). The reproducibility of the proportion of the six-hour MIT completed at 3, 4 and 5 hours was reproducible (between-day CVs ≤ 8.5%). This indicated the suitability to use shorter durations on repeated occasions and a similar percent of the total response to be completed. There was a lack of strong evidence of any relationship between the magnitude of the MIT response and subjective postprandial appetite. Given a six-hour protocol places a considerable burden on participants, these results suggests that a post-meal measurement period of only three hours is sufficient to produce valid information on the metabolic response to a meal. However while there was no mean change in MIT between test days, individual variability was large. Further research is required to better understand which factors best explain the between-day variability in this physiological measure. With such a high prevalence of obesity, dieting has become a necessity to reduce body weight. However, during periods of ER, metabolic and appetite adaptations can occur which may impede weight loss. Understanding how metabolic and appetite factors change during ER and weight loss is important for designing optimal weight loss protocols. The purpose of Study Two was to measure the changes in the MIT response and subjective postprandial appetite during either continuous (CONT) or intermittent (INT) ER and following post diet energy balance (post-diet EB). Thirty-six obese male participants were randomly assigned to either the CONT (Age = 38.6 ± 7.0 years, weight = 109.8 ± 9.2 kg, % fat mass = 38.2 ± 5.2%) or INT diet groups (Age = 39.1 ± 9.1 years, weight = 107.1 ± 12.5 kg, % fat mass = 39.6 ± 6.8%). The study was divided into three phases: a four-week baseline (BL) phase where participants were provided with a diet to maintain body weight, an ER phase lasting either 16 (CONT) or 30 (INT) weeks, where participants were provided with a diet which supplied 67% of their energy balance requirements to induce weight loss and an eight-week post-diet EB phase, providing a diet to maintain body weight post weight loss. The INT ER phase was delivered as eight, two-week blocks of ER interspersed with two-week blocks designed to achieve weight maintenance. Energy requirements for each phase were predicted based on measured RMR, and adjusted throughout the study to account for changes in RMR. All participants completed MIT and appetite tests during BL and the ER phase. Nine CONT and 15 INT participants completed the post-diet EB MIT and 14 INT and 15 CONT participants completed the post-diet EB appetite tests. The MIT test day protocol was as follows: 1) a baseline RMR measured for 30 minutes, 2) a 15-minute break in the measure to consume a standard breakfast meal (874 kcal, 53.3% CHO, 14.5% PRO, 32.2% FAT), and 3) three hours of measuring MIT. MIT was calculated as the energy expenditure above the pre-meal RMR. Appetite test days were undertaken on a separate day using the same 576 kcal breakfast used in Study One. VAS were used to assess appetite pre and post breakfast, at one hour post breakfast then a further three times at 45-minute intervals. Appetite ratings were calculated for hunger and fullness as both the intra-meal change in appetite and the AUC. The three-hour MIT response at BL, ER and post-diet EB respectively were 5.4 ± 1.4%EI, 5.1 ± 1.3%EI and 5.0 ± 0.8%EI for the CONT group and 4.4 ± 1.0%EI, 4.7 ± 1.0%EI and 4.8 ± 0.8%EI for the INT group. Compared to BL, neither group had significant changes in their MIT response during ER or post-diet EB. There were no significant time by group interactions (p = 0.17) indicating a similar response to ER and post-diet EB in both groups. Contrary to what was hypothesised, there was a significant increase in postprandial AUC fullness in response to ER in both groups (p < 0.05). However, there were no significant changes in any of the other postprandial hunger or fullness variables. Despite no changes in MIT in both the CONT or INT group in response to ER or post-diet EB and only a minor increase in postprandial AUC fullness, the individual changes in MIT and postprandial appetite in response to ER were large. However those with the greatest MIT changes did not have the greatest changes in postprandial appetite. This study shows that postprandial appetite and MIT are unlikely to be altered during ER and are unlikely to hinder weight loss. Additionally, there were no changes in MIT in response to weight loss, indicating that body weight did not influence the magnitude of the MIT response. There were large individual changes in both variables, however further research is required to determine whether these changes were real compensatory changes to ER or simply between-day variation. Overall, the results of this thesis add to the current literature by showing the large variability of continuous MIT measurements, which make it difficult to compare MIT between groups and in response to diet interventions. This thesis was able to provide evidence to suggest that shorter measures may provide equally valid information about the total MIT response and can therefore be utilised in future research in order to reduce the burden of long measurements durations. This thesis indicates that MIT and postprandial subjective appetite are most likely independent of each other. This thesis also shows that, on average, energy restriction was not associated with compensatory changes in MIT and postprandial appetite that would have impeded weight loss. However, the large inter-individual variability supports the need to examine individual responses in more detail.

Current methods of energy restriction are not successful for achieving long-term weight loss and maintenance for the majority of individuals. As a result, the prevalence of obesity and obesity related diseases continue to increase. This calls for the development of novel lifestyle interventions to combat the obesity epidemic. Hunger has been highlighted as a major factor influencing the long-term success of weight management methods and therefore how a given dietary intervention affects the appetite regulatory system may dictate the success of the diet by augmenting long-term adherence. In addition, the effect of a given dietary intervention on exercise may determine its suitability for exercising individuals and may influence the energy deficit that can be achieved by the diet. This thesis investigated the acute effects of two novel methods of dietary restriction; breakfast omission and severe energy restriction. The main aims for this thesis were to determine the effect of these methods of energy restriction on ad-libitum energy intake, subjective appetite sensations, and peripheral concentrations of hormones involved in appetite regulation. In addition, this thesis also investigated the effects of these methods of energy restriction on metabolism and glycaemic control at rest, and performance and perceived exertion during exercise. This work found that moderate and severe energy deficits induced by breakfast omission and 24 h of severe energy restriction, respectively, resulted in either no (Chapter VIII) or partial (Chapters IV and VII) energy intake compensation over the subsequent 24-48 h. Subjective appetite was increased during (Chapters IV, V, VII and VIII) and shortly after (Chapter VII) energy restriction, but this effect was transient and was offset after an ad-libitum (Chapters IV and VII) or standardised (Chapters V and VIII) meal. In addition, none of the work presented in this thesis demonstrated an appetite hormone response to energy restriction that was indicative of compensatory eating behaviour. Compared to breakfast omission, breakfast consumption resulted in an increased in resting energy expenditure and carbohydrate oxidation, with a concurrent reduction in fat oxidation during the morning. However, there were no differences after lunch (Chapter V). In response to a standardised breakfast, resting energy expenditure was suppressed (Chapter VII) or not different (Chapter VIII) the following morning, after 24 h severe energy restriction compared to energy balance. Plasma NEFA and fat oxidation was greater, carbohydrate oxidation was reduced, and postprandial insulin sensitivity was impaired in the after 24 h severe energy restriction (Chapter VI, VII and VIII). In Chapter IV, omission of breakfast in the morning was shown to reduce exercise performance in evening, even after provision of an ad-libitum lunch 4 h before. However, there was no difference in perception of effort during steady state exercise, independent of breakfast consumption or omission in the morning (Chapters IV and V). Collectively, breakfast omission and 24 h severe energy restriction reduce energy intake and promote an appetite regulatory response conducive to maintenance of a negative energy balance. Chronic intervention studies are now required to confirm whether these effects persist after long-term practice of these dietary interventions.

Bakgrund: Övervikt och fetma ökar exponentiellt i alla samhällsklasser i alla delar av världen idag. Det kan orsaka lidande och förtida död för de drabbade. Risken att drabbas av våra vanligaste vällevnadssjukdomar som hjärt- och kärlsjukdom, typ 2 diabetes och neurodegenerativa sjukdomar som Alzheimers sjukdom ökar vid övervikt och fetma. Det i särklass mest effektiva sättet att gå ned i vikt är genom att minska sitt kaloriintag. För att behålla en viktnedgång behövs beteendeförändringar, stöttning och en långsiktig plan. Syfte: Syftet med studien är att undersöka om intermittent kalorirestriktion (CR) är mer effektivt än kontinuerlig CR när det gäller viktreduktion och bibehållande av ny vikt. Metod: En litteraturstudie genomfördes där fyra olika parallellstudiers resultat sammanställs. Parallellstudierna jämför effektiviteten av intermittent och kontinuerlig CR på viktreduktion och bibehållande av ny vikt. Resultat: I tre av de fyra studier som undersökts kan inga skillnader i effektivitet uppvisas mellan intermittent och kontinuerlig CR när det gäller viktreduktion och bibehållande av ny vikt över tid. En av studierna fann att intermittent CR, i form av ”week on, week off” två veckor i taget är mer effektiv när det gäller viktreduktion efter 16 veckors interventionsfas samt 6 månader senare. Slutsats: Som alla metastudier jag läst och de flesta studier på ämnet kan ingen skillnad i effektivitet mellan intermittent och kontinuerlig CR uppvisas gällande viktreduktion. Inte heller verkar den ena vara överlägsen den andra när det gäller bibehållande av ny vikt. Fler studier över längre tidsspann med fler deltagare krävs för att kunna dra slutsatser om vilken typ av CR som är mest effektiv på lång sikt.<br>Background: Overweight and obesity are increasing exponentially in all social classes in all parts of the world today. It can cause suffering and premature death to those affected. The risk of suffering from our most common well-being diseases such as cardiovascular disease, type 2 diabetes and neurodegenerative diseases such as Alzheimer's disease increases with overweight and obesity. By far the most effective way to lose weight is by reducing your calorie intake. To maintain a weight loss, behavioural changes, support and a long-term plan are needed. Purpose: The purpose of the study was to investigate whether intermittent calorie restriction (CR) is more effective than continuous CR in terms of weight reduction and maintenance of new weight. Method: A literature study was conducted where the results of four parallel studies were put together. The parallel studies compare the effectiveness of intermittent or continuous CR on weight reduction and maintenance of new weight. Result: In three of the four studies examined, no differences in effectiveness can be demonstrated between intermittent and continuous CR in terms of weight reduction and maintenance of new weight over time. One of the studies found that intermittent CR, in the form of "week on, week off" two weeks at a time, is more effective in weight reduction after 16 weeks of intervention and 6 months later. Conclusion: Like all meta-studies and most studies on the subject, no difference in effectiveness between intermittent and continuous CR can be demonstrated in terms of weight reduction. Nor does one seem superior to the other when it comes to maintaining new weight. More studies over longer time spans with more participants are required to be able to draw conclusions about the type of CR that is most effective in the long term.

Introduction A growing body of evidence, from epidemiological studies in humans and animal models, indicate that maternal health and nutritional status during gestation and lactation can program the propensity to develop obesity in their offspring. Huge efforts are now being directed toward understanding the molecular mechanisms underlying this developmental programming. Identification of these mechanisms could give some clues about potential strategies to prevent or revert programmed propensity to develop obesity, and may help in the identification of early biomarkers. Therefore, the main aim of this PhD-Thesis has been: To characterize in rats the programming effects of moderate maternal energy restriction during pregnancy or lactation on the metabolic health of their offspring in terms of obesity and related metabolic alterations, as well as to identify new preventing strategies against programmed obesity and early biomarkers of metabolic health. Investigation content We have characterized an animal model previously described to exhibit higher propensity to develop obesity and related metabolic alterations ― the offspring of rat dams exposed to moderate food restriction during gestation (CRG) ― to find out some of the potential mechanisms underlying their negative outcomes. Expression levels of key energy homeostasis-related genes in the hypothalamus and adipose tissue, and the measurement of some circulating parameters, showed that these animals were programmed, already from early ages, for a lower capacity to respond to insulin and to central leptin action. This could explain the hyperphagia observed in these animals and the greater propensity for obesity, manifested particularly in males. Some of these programmed disturbances, such as the impaired insulin and leptin sensitivity, and the increased systolic blood pressure, characteristic of CRG-animals, were reverted by enhancing hepatic fatty acid oxidation at early ages, through adeno-associated virus-mediated gene transference of the cDNA of Cpt1am (encoding for a permanently active form of CPT1A insensitive to its physiological inhibitor malonyl-CoA). Unlike calorie restriction during gestation, we show here that moderate calorie restriction in rat dams during lactation protects their offspring (CRL) against diet-induced obesity and related metabolic alterations, such as dyslipidemia, insulin resistance and hyperleptinemia. This condition during lactation determines early changes at gene expression level in WAT and liver, affecting lipogenic and oxidative capacity and increasing their sensitivity to the peripheral effects of leptin and insulin. Some of these adaptations were partially maintained in adulthood. Adult CRL-animals showed gender-dependent changes at gene expression level in adipose tissue and hypothalamus, suggesting that males were more protected against high-fat diet induced peripheral insulin resistance and they also showed improved capacity to respond centrally to leptin, while CRL-females were programmed for a better sensitivity to the peripheral actions of leptin and to the central action of insulin. We used this animal model to identify early transcriptome-based biomarkers of improved metabolic health by whole-genome microarray analysis in peripheral blood mononuclear cells (PBMCs). Concerning the factors potentially involved in the benefits of maternal calorie restriction during lactation on their offspring, the diminished content of markers of protein damage by oxidation and glycation found in breast milk from CRL-dams, in comparison to milk from controls, could be relevant. Conclusion Maternal nutrition during the perinatal period may be an important determinant of insulin and leptin sensitivity in their offspring. While calorie restriction during pregnancy programs their offspring for a lower capacity to respond to insulin and to central leptin action, the offspring of calorie restricted lactating dams show enhanced sensitivity to these hormones. Expression levels in blood cells of a set of genes are proposed as potential early biomarkers of metabolic health, and hence may provide a valid biological readout for the study of metabolic processes in humans.<br>Introducción Numerosas evidencias, procedentes de estudios epidemiológicos en humanos y de modelos animales, indican que la salud materna y su estado nutricional durante la gestación y la lactancia pueden programar la propensión a desarrollar obesidad en la descendencia. Se están llevando a cabo grandes esfuerzos para entender los mecanismos moleculares responsables de dicha programación metabólica. La identificación de los mecanismos responsables podría dar ciertas pistas para el desarrollo de estrategias que permitan prevenir o revertir dicha propensión a desarrollar obesidad, y también podría ayudarnos en la identificación de biomarcadores tempranos de salud metabólica. Por consiguiente, el principal objetivo de esta tesis doctoral ha sido: Caracterizar en ratas los efectos de una restricción energética materna moderada durante la gestación o la lactancia sobre la salud metabólica de la descendencia, en relación a la obesidad y las alteraciones metabólicas asociadas, así como también identificar nuevas estrategias de prevención frente la programación de la obesidad y nuevos biomarcadores tempranos de salud metabólica. Contenido de la investigación Hemos caracterizado un modelo animal, que previamente se había descrito que presentaba una mayor propensión a desarrollar obesidad y alteraciones metabólicas asociadas – las crías de ratas sometidas a una restricción calórica moderada durante la gestación (CRG) – para identificar algunos de los mecanismos potencialmente responsables de sus efectos negativos. Los niveles de expresión de genes claves relacionados con la homeostasia energética en el hipotálamo y el tejido adiposo, y el análisis de ciertos parámetros circulantes, revelaron que estos animales estaban programados, ya desde edades tempranas, para una menor respuesta a la insulina y a la acción central de la leptina. Esto podría explicar la hiperfagia observada en estos animales y la mayor propensión a la obesidad, que presentan particularmente los machos. Algunas de estas alteraciones programadas, tales como la alteración de la sensibilidad a la insulina y a leptina, y la elevada presión sistólica, característica de los animales CRG, se vieron revertidas al favorecer el incremento de la oxidación hepática de ácidos grasos, en edades tempranas, a través de la transferencia génica, mediada por vectores virales adeno-asociados, del ADNc de la Cpt1am (que codifica para una forma permanentemente activa de la CPT1A, insensible a su inhibidor fisiológico malonil-CoA). A diferencia de la restricción calórica durante la gestación, observamos que la restricción calórica moderada en ratas madre durante la lactancia protege a su descendencia (CRL) frente al desarrollo de obesidad inducida por la dieta y frente al desarrollo de alteraciones metabólicas asociadas, tales como la dislipidemia, la resistencia a la insulina y la hiperleptinemia. Esta condición durante la lactancia determina cambios tempranos a nivel de expresión génica en el tejido adiposo y el hígado, afectando la capacidad lipogénica y oxidativa, e incrementando la sensibilidad a la acción periférica de la insulina y la leptina. Algunas de estas adaptaciones se mantuvieron parcialmente en edad adulta. Los animales CRL adultos mostraron cambios a nivel de expresión génica en el tejido adiposo y en el hipotálamo que fueron dependientes del sexo, sugiriendo que los machos estaban más protegidos frente a la resistencia periférica a la insulina inducida por una dieta hiperlipídica, así como también mostraron una capacidad mejorada para responder a la leptina a nivel central; en cambio, las hembras CRL estaban programadas para una mejor sensibilidad a la acción periférica de la leptina y a la acción central de la insulina. Utilizamos este modelo animal para identificar marcadores tempranos de transcripción indicadores de salud metabólica mejorada mediante el análisis por microarray de células mononucleares de sangre periférica (PBMCs). Con respecto a los factores que podrían estar potencialmente implicados en los efectos beneficiosos de la restricción calórica durante la lactancia sobre las crías, el menor contenido de marcadores de daño proteico por oxidación y glicación hallado en la leche de madres CRL, en comparación con la leche de madres control, podría ser relevante. Conclusión La nutrición materna durante el periodo perinatal puede ser un determinante importante de la sensibilidad a la insulina y la leptina de sus crías. Mientras que la restricción calórica durante la gestación programa a las crías para una menor capacidad de respuesta a la inulina y a la acción central de la leptina, las crías de madres expuestas a una restricción calórica moderada durante la lactancia muestran una sensibilidad mejorada a estas hormonas. Se han identificado un grupo de genes cuyos niveles de expresión en células sanguíneas podrían considerarse como potenciales marcadores tempranos de salud metabólica, pudiendo proporcionar una herramienta biológica válida para el estudio de procesos metabólicos en humanos.<br>Introducció Nombroses evidències, procedents d’estudis epidemiològics en humans i de models animals, indiquen que la salut materna i el seu estatus nutricional durant la gestació i la lactància poden programar la propensió de la descendència a desenvolupar obesitat. S’estan duent a terme grans esforços per entendre els mecanismes moleculars responsables d’aquesta programació metabòlica. La identificació d’aquests mecanismes podria donar-nos certes pistes per al desenvolupament d’estratègies que permetin prevenir o revertir la propensió programada a desenvolupar obesitat, i també podria ajudar-nos en la identificació de biomarcadors primerencs de salut metabòlica. Per això, el principal objectiu d’aquesta tesis doctoral ha estat: Caracteritzar en rates els efectes d’una restricció energètica moderada a les mares durant la gestació o la lactància sobre la salut metabòlica de la descendència, en relació a l’obesitat i les alteracions metabòliques associades, així com també identificar noves estratègies de prevenció enfront a la programació de l’obesitat i nous biomarcadors primerencs de salut metabòlica. Contingut de la investigació Hem caracteritzat un model animal, que prèviament se va veure que exhibia una major propensió a desenvolupar obesitat i alteracions metabòliques associades – les cries de rates sotmeses a una restricció calòrica moderada durant la gestació (CRG) – per identificar alguns dels mecanismes potencialment responsables dels seus efectes negatius. Els nivells d’expressió de gens clau relacionats amb la homeòstasi energètica a l’hipotàlem i al teixit adipós, i l’anàlisi de certs paràmetres circulants, varen mostrar que aquests animals estaven programats, ja des d’etapes primerenques de la vida, per una menor resposta a la insulina i a la acció central de la leptina. Això podria explicar la hiperfàgia observada en aquests animals i la major propensió a l’obesitat, que presenten particularment els mascles. Algunes d’aquestes alteracions programades, com ara l’alteració de la sensibilitat a la insulina i a la leptina, i l’elevada pressió sistòlica, característica dels animals CRG, es van veure revertides en afavorir l’increment de la oxidació hepàtica dels àcids grassos, a edats primerenques, a través de la transferència gènica, mitjançant vectors virals adeno-associats, de l’ADNc de la Cpt1am (que codifica per una forma permanentment activa de la CPT1A, insensible al seu inhibidor fisiològic, el malonil-CoA). A diferència de la restricció calòrica durant la gestació, observarem que la restricció calòrica moderada en rates mare durant la lactància, protegeix a la seva descendència (CRL) enfront del desenvolupament d’obesitat induïda per la dieta i el desenvolupament d’alteracions metabòliques associades a l’adultesa, com ara la dislipèmia, la resistència a la insulina i la hiperleptinèmia. Aquesta condició durant la lactància determina canvis primerencs a nivell d’expressió gènica en el teixit adipós i en el fetge, afectant la capacitat lipogènica i oxidativa, i incrementant la sensibilitat a la acció perifèrica de la insulina i la leptina. Algunes d’aquestes adaptacions se varen mantenir parcialment en edat adulta. Els animals adults CRL varen mostrar canvis en els nivells d’expressió gènica en el teixit adipós i a l’hipotàlem, que varen ser dependents del sexe, suggerint que els mascles estaven més protegits enfront a la resistència perifèrica a la insulina induïda per una dieta hiperlipídica, i també mostraren una capacitat millorada per respondre a la leptina a nivell central; en canvi, les femelles CRL estaven programades per a una millor sensibilitat a l’acció perifèrica de la leptina i a la acció central de la insulina. Utilitzarem aquest model animal per a la identificació de biomarcadors primerencs de transcripció, indicadors de salut metabòlica millorada, mitjançant l’anàlisi per microarray en cèl•lules mononuclears de sang perifèrica (PBMCs). Pel que fa als factors que podrien estar potencialment implicats en els efectes beneficiosos de la restricció calòrica materna durant la lactància sobre la descendència, el menor contingut de marcadors de dany proteic per glicació i d’oxidació trobat a la llet de mares CRL, en comparació amb la llet de mares control, podria ser rellevant. Conclusió La nutrició materna durant el període perinatal pot ser un determinant important de la sensibilitat a la insulina i a la leptina de les seves cries. La restricció calòrica durant la gestació programa a les cries per a una menor resposta a la insulina i a la acció central de la leptina; en canvi, les cries de mares exposades a una restricció calòrica moderada durant la lactància mostren una major sensibilitat a aquestes hormones. S’han identificat un grup de gens, els nivells de expressió dels quals en cèl•lules sanguínies se poden considerar com a potencials marcadors primerencs de salut metabòlica, podent proporcionar una eina biològica vàlida per a l’estudi dels processos metabòlics en humans.

Bakgrund: Allt fler individer i välutvecklade länder kan klassificeras som överviktiga. Övervikt och fetma ökar risken för en mängd olika sjukdomar och är en av de främsta orsakerna till sjukdomsbördan och för tidig död i Sverige. Det finns därför behov för att kunna rekommendera effektiva kostinterventioner. Kontinuerlig energirestriktion är den vanligaste kostinterventionen, men det finns behov för att kunna rekommendera alternativa kostinterventioner.Syfte: Syftet med denna litteraturstudie var att sammanställa resultaten från randomiserade kontrollerade studier från de senaste fem åren som undersöker effekten av intermittent fasta och tidsbegränsat energiintag jämfört med kontinuerlig energirestriktion på viktreduktion och kroppskomposition.Metod: Litteratursökningen gjordes i databaserna Web of Science och PubMed. Sökningen resulterade i 612 träffar varav tio inkluderades i studien.Resultat: Tre av tio studier påvisade skillnader mellan kostinterventionerna gällande viktreduktion; en till fördel för intermittent fasta jämfört med kontinuerlig energirestriktion (p&lt;0,01) en till fördel för tidsbegränsat energiintag jämfört med kontinuerlig energirestriktion (p&lt;0,05) och en till fördel för kontinuerlig energirestriktion jämfört med intermittent fasta (p&lt;0,05). Två av tio studier påvisade skillnad mellan kostinterventionerna i mängden tappad fettmassa till fördel för intermittent fasta (p&lt;0,01) och tidsbegränsat energiintag (p&lt;0,05) jämfört med kontinuerlig energirestriktion.Konklusion: Intermittent fasta och tidsbegränsat energiintag har i denna litteraturöversikt visat på likvärdiga resultat på viktreduktion och kroppskomposition jämfört med kontinuerlig energirestriktion. Resultaten i de granskade studierna tyder på att det är följsamheten av kostinterventionen som är avgörande för viktreduktion och inte själva kostinterventionen i sig.<br>Background: There is an increase in overweight and obese people around the world. Overweight and obesity increases the risk of multiple diseases and comorbidities. Continuous energy restriction is the most used diet method. However, research suggests that adherence to the diet diminishes within a couple of months, therefore research in alternative methods has increased. Objectives: The objectives of this literature review were to review the latest literature since 2017 regarding the effects of intermittent fasting and time-restricted feeding compared to continuous energy restriction on weight loss and body composition.Methods: The literature search was done in Web of Science and PubMed. The search resulted in 612 articles. Ten of the 612 articles were included in the literature review.Results: Three out of ten studies showed significant differences between groups regarding weight loss. One in favor of intermittent fasting compared to continuous energy restriction (p&lt;0,01), one in favor of time-restricted feeding compared to continuous energy restriction (p&lt;0,05) and one in favor of continuous energy restriction compared to intermittent fasting (p=0,03). Two out of ten studies showed a significant difference between groups regarding reduction of fat mass in favor of intermittent fasting (p&lt;0,01) and time-restricted feeding (p&lt;0,05) compared to continuous energy restriction.Conclusion: This literature review suggests that intermittent fasting and time-restricted feeding when compared to continuous energy restriction has similar effects on weight loss and body composition. The results of the studies suggest that it is the adherence of the diet that is vital for successful weight loss and not the diet itself.

Normal nutritional function requires a healthy diet. Healthy eating incorporates a variety of nutrients that are essential for energy expenditure, prevention of disease, and maintenance of normal physiological function. An unhealthy diet can result in malnutrition, and this contributes to illness and death throughout the world. The core principle of healthy eating is obtaining an adequate balance, and the diseases resulting from overnourishment differ greatly from those resulting from undernourishment. In the third world, diets tend to rely heavily on staple crops, and can be very seasonal. Energy sources are predominantly cereals, whereas meat and fish are limited. Malnutrition tends to occur from a lack of essential nutrients, leading to conditions such as vitamin deficiencies, kwashiorkor, and iodine deficiency syndromes. In first-world countries, people have more freedom to choose what they eat. Thus, diets tend to be high in fat and dense in energy. Obesity, diabetes, coronary heart disease, cancer, and hypertension are major contributors to morbidity and mortality. A healthy diet should contain adequate proportions of carbohydrates, fats, proteins, vitamins, and trace elements. The intake of these constituents is sporadic, with meals constituting major boluses of potential energy. Energy expenditure, conversely, is continuous. The human body has, therefore, developed complex mechanisms directing nutrients into storage when in excess, and mobilizing these stores as they are needed, and it is essential that sufficient energy is always available to maintain the basal metabolic rate, which is the amount of energy expended while at rest in a neutrally temperate environment. This energy is sufficient only for the functioning of the vital organs, such as the heart, the lungs, the liver, the kidneys, and the CNS.

The current approach to managing diabetes mellitus in obese patients focuses on a comprehensive strategy that addresses both conditions simultaneously. Central to this approach is weight management through lifestyle modifications, including dietary changes and increased physical activity. Caloric restriction, with an emphasis on balanced nutrition that limits simple sugars and unhealthy fats while promoting fiber-rich foods, plays a crucial role. Regular exercise helps improve insulin sensitivity and facilitates weight loss. Pharmacotherapy may include medications that not only lower blood glucose levels but also aid in weight reduction, such as GLP-1 receptor agonists and SGLT-2 inhibitors. These agents have shown benefits beyond glycemic control by promoting weight loss and reducing cardiovascular risk factors. Bariatric surgery is considered for severely obese individuals with diabetes which is difficult to control with lifestyle modifications and medications alone. It can lead to significant weight loss and often results in remission or improvement of diabetes. Continuous monitoring of blood glucose levels, along with regular assessments of lipid profiles, kidney function, and cardiovascular risk factors, guides treatment adjustments and helps prevent complications. Patient education and ongoing support are essential to promote adherence to treatment plans and empower individuals to manage both diabetes and obesity effectively. Integrating these approaches ensures a holistic and personalized management strategy tailored to the unique needs of obese patients with diabetes mellitus.

Abstract Diabetes and obesity remain two of the most prominent diseases and causes of morbidity and mortality in the United States and across the world. Approaches to curbing these epidemics primarily revolve around lifestyle adjustments to diet and exercise. However, recent research continues to further inform the important role that sleep deficiency and sleep health behaviors play in diabetes, obesity, and health. Both sleep restriction and circadian disruption represent risk factors for weight gain and diabetes, via physiological mechanisms including adverse impacts on glucose and lipid metabolism, and energy expenditure. This chapter summarizes evidence from epidemiological and experimental laboratory studies regarding a role for sleep health in metabolism, obesity, and diabetes.

This chapter explores the physiology and pathophysiology of obesity and provides an overview of its medical management. In spite of recognizing the medical problems associated with obesity, it was 2013 when the American Medical Association acknowledged it as a disease; thereafter, medical societies began treating it as such. Understanding body weight regulation requires an understanding of energy balance. There are three main factors that affect and maintain energy balance and a steady body weight—the homoeostatic, environmental, and behavioural processes. Alterations in any of these may lead to weight changes. Although weight loss can usually be achieved through restriction of caloric intake and/or increased physical activity, most individuals have a tendency to regain the lost weight. A plausible hypothesis is that body weight is maintained at a particular set level, and deviations from this set point are resisted and minimized by a feedback control system. Diet, exercise, and behavioural modifications should be all parts of obesity management, with adjunctive pharmacotherapy as necessary. In patients with extreme obesity, however, bariatric surgery is the best alternative treatment.

Sarcopenic obesity is a skeletal muscle weight loss disease. It has happened at an elderly age. A ketogenic diet is a low-carbohydrate (5%), moderate protein (15%), and a higher-fat diet (80%) can help sarcopenic obese patients burn their fat more effectively. It has many benefits for muscle and fat weight loss. A ketogenic diet can be especially useful for losing excess body fat without hunger and for improving type 2 diabetes. That is because of only a few carbohydrates in the diet, the liver converts fat into fatty acids and ketones. Ketone bodies can replace higher ATP energy. This diet forces the human body to burn fat. This is a good way to lose fat weight without restriction.

Objective; Obesity is an important health problem, leading to many metabolic diseases such as type2 diabetes mellitus, cardiovascular diseases, cancer. The are many diet proposals to combat obesity. Since obesity is relatively rare in Japan, we wante to know what kind of foods influence body mass index (BMI) in old Japanese people. METHODS; Healthy participants, old men and women and male medical doctors (MD) were given self-administered diet history questionnaires and described answers on each item by recollection of diets they took (7 days dietary recall). We used a brief-type self-administered diet history questionnaire (BDHQ) by using which the Japanese Ministry of Health, Labour and Welfare reports national Nutrition Surveys. From these questionnaires, we calculated the intakes of energy, carbohydrate, fat, protein or other foods. RESULTS; Me take more alcohol, salt fruit, beans than women. Intakes of major foods such as carbohydrate, lipid, and protein did not influence BMI in men and women. MD with higher BMI tend to take vegetables and fruits. MD may be more health concerned than lay people. CONCLUSION; within the range of foods intakes in Japan, no restriction of any food such as carbohydrate is not necessary for staying lean. Medical doctors seem to be very health concerned compared to lay people.

Mitochondria play a central role in cellular energy production, metabolic regulation, and oxidative stress management. Their dysfunction is a hallmark of cardiometabolic diseases, including obesity, diabetes, metabolic-associated steatotic liver disease (MASLD), and cardiovascular disease (CVD). Mitochondrial decline, characterized by impaired oxidative phosphorylation, excessive reactive oxygen species (ROS) production, and mitochondrial DNA (mtDNA) mutations, also accelerates aging and contributes to cellular senescence and metabolic dysregulation. This chapter explores the essential role of mitochondrial health in cardiometabolic diseases and aging, focusing on emerging therapeutic strategies to restore mitochondrial function. Therapeutic fasting, including intermittent fasting and caloric restriction, has shown significant potential to enhance mitophagy, promote mitochondrial biogenesis, and improve oxidative efficiency. Concurrently, natural supplements such as resveratrol, curcumin, spermidine, and green tea polyphenols including vitamins have demonstrated efficacy in mitigating oxidative stress, preserving mtDNA integrity, and supporting electron transport chain activity. This chapter highlights the therapeutic mechanisms and the potential of therapeutic fasting and natural supplements in addressing mitochondrial dysfunction, offering innovative approaches to manage cardiometabolic diseases, extend healthspan, and combat aging-related disorders. The chapter also discusses the challenges and future directions for translating these findings into clinical practice.

Despite the various treatment methods that exist for obesity, the most effective treatment for long-term weight control is bariatric surgery. Different surgical methods affect different mechanisms, such as appetite change, restriction of intake, and control of hunger. Divert food from the proximal part of the small intestine, food aversion, increased energy expenditure, malabsorption of macronutrients, and modifications of bile aside profiles and the gut microbiota. Gut microbiota plays an important role in maintaining human health. Dysbiosis usually has detrimental effects and may also have long-term consequences that lead to diseases or disorders, such as diabetes, obesity, and inflammatory bowel disease. While Firmicutes are abundant in the gut microbiota of obese individuals, Bacteroidetes are more abundant in individuals with normal weight. Thus, specific changes in the gut microbial composition are associated with obesity. The suggestion of growing evidence of bariatric surgery’s success is because of the procedure’s effect on the gut microbiota. Bariatric surgery changes the short-chain fatty acids composition by certain changes in the gut microbiota, thus affecting host metabolism, including intestinal hormone secretion and insulin sensitivity. Different methods of bariatric surgery alter the gut microbiota differently.

The global rise in obesity highlights the need for personalized weight management strategies that account for individual metabolic and hormonal differences, moving beyond the simplistic “calories in, calories out” approach. Body types—ectomorph, mesomorph, and endomorph—serve as a framework for understanding variations in fat storage, muscle development, and energy expenditure. These differences are influenced by genetic, epigenetic, and lifestyle factors, including nutrition, exercise, sleep, and stress. Such factors affect processes like lipogenesis, myofibrillar protein synthesis during overfeeding, and lipolysis and muscle proteolysis during caloric restriction. Precision approaches, such as nutrigenomics, indirect calorimetry, and AI-based strategies, can help tailor weight management plans to an individual's unique metabolic profile. This chapter explores the metabolic and hormonal adaptations that contribute to variability in weight management outcomes and discusses how precision nutrition can offer personalized, effective solutions for sustainable weight management.

Abstract The stated aim of this book was to develop Monte Carlo simulations that were accurate enough to be useful predictive tools but simple enough to be accessible to nonspecialists. The previous chapters of the book have demonstrated that, within these limits, a great deal can be done. However, in meeting these goals, approximations and simplifications have had to be made. Specifically, we have made the assumptions that only elastic scattering, as described by the Rutherford cross section, need be considered and that energy loss can be treated as a continuous rather than as a discrete process. Such assumptions are not essential to the construction of a Monte Carlo simulation of electron scattering, and so the obvious and desirable move is to remove these approximations for those cases where they represent an unacceptable restriction.

In North America, 60% of cats is estimated to be overweight or obese, predisposing cats to obesity-related health consequences, which reduce quality and quantity of life. Weight loss is recommended, yet current protocols are often unsuccessful. Moreover, drastic energy restriction can put overweight and obese cats at risk of developing feline hepatic lipidosis which can be fatal if left untreated.Choline, an essential nutrient, can be found naturally in organ meats, eggs, soybean and wheat germ. Commercial pet foods contain a supplemental source of choline to meet the recommendations set by the Association of American Feed Control Officials. For cats, 2400 mg/kg diet on a dry matter basis or 600 mg/1000 kcal metabolizable energy is recommended for growth and adult maintenance. Choline is a methyl group donor involved in multiple metabolic pathways and plays an important role in fat metabolism and mobilization, particularly in the liver. Choline is a precursor for phosphatidylcholine, an essential component of very-low-density lipoproteins, crucial for exporting triglycerides and cholesterol out of the liver and into circulation. Research in many animal species, including cats, has found that a diet deficient in choline results in hepatic fat accumulation. Similarly in rats, high-fat diet-induced fatty livers were reversed with choline. Choline supplementation studies in the animal nutrition field have largely focused on growth and weight gain in livestock. This research uncovered decreased fat deposition and increased lean carcass composition with supplementation of choline or its derivative betaine. &#x0D;This session will summarize recent choline research in cats. The findings suggest that supplementing choline, above an animal’s recommended allowance, may help to reduce body fat gain in growing kittens after neutering, and help mobilize fats from the liver in overweight and obese cats, proposing a novel nutritional strategy for obesity prevention and liver health in domestic cats.

Abstract Continuous flow gas lift is one of the most common artificial lift method in the oil industry and is widely used in the world. A continuous volume of gas is injected at high pressure into the bottom of the tubing, to gasify the oil column and thus facilitate the extraction. If there is no restriction in the amount of injection gas available, sufficient gas can be injected into each oil well to reach maximum production. However, the injection gas available is generally insufficient. An inefficient gas allocation in a field with limited gas supply also reduces the revenues, since excessive gas injection is expensive due to the high gas prices and compressing costs. Therefore, it is necessary to assign the injection gas into each well in optimal form to obtain the field maximum oil production rate. The gas allocation optimization can be considered as a maximization of a nonlinear function, which models the total oil production rate for a group of wells. The variables or unknowns for this function are the gas injection rates for each well, which are subject to physical restrictions. In this work a MATLAB™ nonlinear optimization technique with constraints was implemented to find the optimal gas injection rates. A new mathematical fit to the “Gas-Lift Performance Curve” is presented and the numeric results of the optimization are given and compared with results of other methods published in the specialized literature. The optimization technique proved fast convergence and broad application.

Abstract Heating, ventilation and air-conditioning (HVAC) systems can consume over 5 quads of energy annually, representing 30% of energy consumption in the U.S. in commercial buildings. Additionally, commercial refrigeration (R) systems add about 2 quads to commercial buildings energy consumption. Most HVAC systems have one or more faults (low/high refrigerant charge, valve leakage, condenser/evaporator fouling, filter/dryer restriction, economizer faults, controls faults) that result in increased energy consumption. Automated fault detection and diagnosis (AFDD) tools have been developed to address this national issue and many tools are commercially available. AFDD tools have the potential to save considerable energy for existing commercial RTUs, chillers and refrigeration systems. These devices can be used for both retro commissioning, and, when faults are addressed, continuous commissioning as well. However, there appears to be multiple market barriers for this technology. A key market barrier for this technology is the lack of awareness of AFDD products among potential customers. Most HVAC contractors are not familiar with the latest AFDD technologies and HVAC technicians lack skills regarding these technologies. Quantifying potential benefits to building owners is difficult since there are several FDD tools with varying capabilities. For instance, there are several FDD products ranging from handling just economizer faults to those that also handle full-blown refrigerant-side and air-side faults. Methods/algorithms used in FDD vary significantly. Even though there are efforts to develop standards, currently there are no standards/methods to define functions, capabilities, accuracy, and reliability of FDD tools. Moreover, most of the commercial AFDD tools have not been verified in the field independently. This paper presents a comprehensive approach to bringing HVAC AFDD tools into the mainstream. The approach involves demonstrating ten commercially available tools at ten different sites, independent testing and evaluation of the FDD tools, communication with various stakeholders, identifying market barriers, and assisting utility companies in developing incentive programs. This paper presents selection of AFDD tools, site identification, and field testing and evaluation method.

Review question / Objective: P: Adults with overweight or obesity; I: Time restricted eating with eating window less than 10 hours and with or without calorie restriction; C: People with eating window more than 12 hours; O: Weight loss, body composition, metabolic risk factors, energy intake and eating window. Condition being studied: Adults with overweight and obesity. Information sources: We search four databases including PubMed, Embase, Scopus and the Cochrane library.