How dieting might make some fatter: modeling weight cycling toward obesity from a perspective of body composition autoregulation

Association between Diet Quality and Eating Behavior in Type 2 Diabetes Adults: A Cross-Sectional Study

Type 2 diabetes mellitus (T2DM) has become a global epidemic. To effectively control T2DM, individuals must adhere to a high-quality diet that encompasses not only healthy dietary patterns but also promotes positive eating behaviors. We conducted a cross-sectional study on 314 patients with T2DM, and we evaluated the diet quality and also examined the associations between eating behavior, diet quality, and anthropometric and clinical factors in T2DM patients. We used the Diet Quality Index-International and Dutch Eating Behavior Questionnaire to assess dietary characteristics. We found that women had a significantly higher diet quality than men (61.40 vs. 58.68, p = 0.002) but were also more prone to emotional eating (2.00 vs. 1.53, p < 0.001) and restrained eating (2.39 vs. 2.05, p = 0.002). Restrained eating correlated with duration of diabetes (r = -0.169, p = 0.003), body mass index (r = 0.182, p = 0.001), and external eating with glycated hemoglobin (r = 0.114, p = 0.044). Patients with emotional eating had a higher vitamin C adequacy score (β = 0.117, p = 0.045). External eating was positively associated with grain adequacy (β = 0.208, p < 0.001) and negatively associated with empty-calorie food moderation score (β = -0.125, p = 0.032). For restrained eating, we found associations with vitamin C adequacy (β = -0.138, p = 0.017) and fruit adequacy (β = 0.125, p = 0.033). In conclusion, the results of this study provide valuable insight into dietary behavior and emphasize the importance of promoting healthy eating habits for T2DM patients.

Role of food choice motives in the socio-economic disparities in diet diversity and obesity outcomes in Kenya

BACKGROUND

The increased prevalence of overweight and obesity, along with high diet diversity, is observed among higher socio-economic groups in Sub-Saharan Africa. One contributing factor to these observed variations is food choice motives. However, the role of these motives in explaining the observed differences has not been thoroughly explored in this context.

OBJECTIVE

This study investigates whether there are significant differences in food choice motives among socio-economic groups and whether these variations can partly explain the socio-economic disparities in diet diversity and overweight and obesity outcomes.

METHODS

This study utilizes cross-sectional data from four counties in Kenya: Kiambu, Murang'a, Uasin Gishu, and Nakuru. The survey employed a three-stage cluster sample design to gather data using structured questionnaires on food choice motives, diet diversity, and anthropometrics from 381 adults in 2022. The mediating effects of 8 food choice motives (health, mood, convenience, sensory appeal, natural content, price, weight control, and familiarity) were analyzed using the Karlson-Holm-Breen method.

RESULTS

The results show that individuals with higher household incomes place greater importance on health, mood, sensory, and weight concerns. The probability of an overweight and obesity outcome increases by 19% for a standard deviation change in the asset score, and by 8% for a standard deviation change in the years of schooling. Sensory motives significantly mediated these relationships. Sensory motives explained 29% of the income-BMI association and 30% of the education-BMI relationship. Higher education was also associated with increased diet diversity (β = 0.36, P < 0.001) mediated by higher health and sensory concerns.

CONCLUSIONS

The findings suggest significant differences in food choice motives among socio-economic groups, which contribute to outcomes such as overweight and obesity. Therefore, educational and other policies aimed at reducing obesity should also address food choice motives, while considering the disparities among socio-economic segments within populations.

Impact of weight loss and weight gain trajectories on body composition in a population at high risk of type 2 diabetes: A prospective cohort analysis

AIM

In a primary care population at high risk of type 2 diabetes, 24-month weight change trajectories were used to investigate the impact of weight cycling on fat mass (FM) and fat-free mass (FFM).

MATERIALS AND METHODS

Cohort data from the Walking Away from Type 2 Diabetes trial was used, which recruited adults at-risk of type 2 diabetes from primary care in 2009/10. Annual weight change trajectories based on weight loss/gain of ≥5% were assessed over two 24-month periods. Body composition was measured by bioelectrical impedance analysis. Repeated measures were analysed using generalized estimating equations with participants contributing up to two 24-month observation periods.

RESULTS

In total, 622 participants were included (average age = 63.6 years, body mass index = 32.0 kg/m2 , 35.4% women), contributing 1163 observations. Most observations (69.2%) were from those that maintained their body weight, with no change to FM or FFM. A minority (4.6% of observations) lost over 5% of body weight between baseline and 12 months, which was then regained between 12 and 24 months. These individuals regained FM to baseline levels, but lost 1.50 (0.66, 2.35) kg FFM, adjusted for confounders. In contrast, those that gained weight between baseline and 12 months but lost weight between 12 and 24 months (5.5% of observations) had a net gain in FM of 1.70 (0.27, 3.12) kg with no change to FFM.

CONCLUSION

Weight cycling may be associated with a progressive loss in FFM and/or gain in FM in those with overweight and obesity at-risk of type 2 diabetes.

Role of Endogenous Opioids in the Pathophysiology of Obesity and Eating Disorders

This second chapter in our trilogy reviews and critically appraises the scientific evidence for the role of endogenous opioid system (EOS) activity in the onset and progression of both obesity and eating disorders. Defining features of normative eating and maladaptive eating behaviors are discussed as a foundation. We review the scientific literature pertaining to the predisposing risk factors and pathophysiology for obesity and eating disorders. Research targeting the association between obesity, disordered eating, and psychiatric comorbidities is reviewed. We conclude by discussing the involvement of endogenous opioids in neurobiological and behavior traits, and the clinical evidence for the role of the EOS in obesity and eating disorders.

Relationships Between Three Eating Behaviors and Nine Motives for Food Choices Among Brazilian Adults: A Structural Equation Model

We examined the relationships between three eating behaviors and nine motives underlying food choices made by Brazilian adults. Using participant responses to the short version of the Three-Factor Eating Questionnaire and the Food Choice Questionnaire, we investigated eating behaviors (cognitive restriction, uncontrolled eating, and emotional eating) and motives for food choices (health, mood, convenience, sensory appeal, natural content, price, weight control, familiarity, and ethical concern). We used a structural equation model to test relationship pathways (β), with eating behaviors as independent variables and motives for food choices as dependent variables. Participants were 1297 individuals (69.5% female) with a mean age of 25.0 years (SD = 5.8). We confirmed the validity and reliability of the questionnaires in this sample. Restrictive eating behavior was significantly related to motives of health (β = .415), mood (β = .127), natural content (β = .364), weight control (β = .681), and ethical concern (β = .161). Emotional eating behavior was related to motives of mood (β = .277), health (β = -.137), and natural content (β = -.136). Uncontrolled eating behavior was related to motives of convenience (β = .226), sensory appeal (β = .121), price (β = .153), and familiarity (β = .090). We believe these findings can now help design future research and clinical interventions for managing people's risky eating behaviors and promoting beneficial food choices.

Effects of Diet Macronutrient Composition on Weight Loss during Caloric Restriction and Subsequent Weight Regain during Refeeding in Aging Mice

Caloric restriction (CR) induces weight loss, but is associated with rapid weight regain upon return to ad libitum feeding. Our aim was to investigate effects of the macronutrient composition of the diet on weight loss and regain in elderly mice. Males, 18 months old, of the C57BL/6J strain were subjected to 4-week 30% CR followed by 4 weeks of ad libitum refeeding on either high-carb (HC), high-fat (HF) or high-protein (HP) diets (n = 22 each). Mice (n = 11) fed a chow diet ad libitum served as a control group (CON). Body mass and food intake were monitored daily. Twenty-four-hour indirect calorimetry was used to assess energy expenditure and substrate oxidation. Muscle and fat mass were evaluated with dissection of the tissues. Serum leptin and ghrelin levels were also measured. CR-induced weight loss did not differ between the diets. Weight regain was particularly fast for HF as mice overshot their initial weight by 12.8 ± 5.7% after 4-week refeeding when HC and HP mice reached the weight of the CON group. Weight regain strongly correlated with energy intake across the groups. The respiratory exchange ratio was lower in HF mice (0.81 ± 0.03) compared to HC (0.94 ± 0.06, p < 0.001), HP (0.89 ± 0.04, p < 0.001) and CON mice (0.91 ± 0.06, p < 0.01) during the refeeding. Serum leptin levels were higher in HF mice (1.03 ± 0.50 ng/mL) compared to HC (0.46 ± 0.14, p < 0.001), HP (0.63 ± 0.28, p < 0.05) or CON mice (0.41 ± 0.14, p < 0.001). Thus, CR induces similar weight loss in aging mice irrespective of the diet's macronutrient composition. An HF diet leads to excessive energy intake and pronounced gain in body fat in spite of increased fat oxidation and serum leptin during the refeeding after CR.

Is dieting a risk for higher weight gain in normal-weight individual? A systematic review and meta-analysis

While there is an increasing prevalence of dieting in the overall population, weight loss (WL) practices could be a risk factor for weight gain (WG) in normal-weight (NW) individuals. The aim of the present work was to systematically review all the studies implicating diet restriction and body weight (BW) evolution in NW people. The literature search was registered in PROSPERO (CRD42021281442) and was performed in three databases from April 2021 to June 2022 for articles involving healthy NW adults. From a total of 1487 records initially identified, eighteen were selected in the systematic review. Of the eight dieting interventional studies, only one found a higher BW after weight recovery, but 75 % of them highlighted metabolic adaptations in response to WL favouring weight regain and persisting during/after BW recovery. Eight of the ten observational studies showed a relationship between dieting and major later WG, while the meta-analysis of observational studies results indicated that 'dieters' have a higher BW than 'non-dieters'. However, considering the high methodological heterogeneity and the publication bias of the studies, this result should be taken with caution. Moreover, the term 'diet' was poorly described, and we observed a large heterogeneity of the methods used to assess dieting status. Present results suggest that dieting could be a major risk factor for WG in the long term in NW individuals. There is, however, a real need for prospective randomised controlled studies, specifically assessing the relationship between WL induced by diet and subsequent weight in this population.

Effect of a lifestyle intervention to prevent weight gain at initiation of insulin pump therapy in type 2 diabetes: a randomized, controlled, multicentre trial

Insulin pump therapy improves glycaemic control in individuals with type 2 diabetes. However, it may be associated with weight gain.

AIM

To test the effectiveness of a six-month dietary and physical activity intervention, compared to usual care, on weight gain prevention after initiation of insulin pump.

METHODS

Multicentre randomized, controlled trial of 54 individuals. Primary endpoint was between group difference in weight gain at six-months.

RESULTS

Weight gain after 6 months of insulin pump treatment did not differ between groups: mean 3.2 (3.9) kg in the control group and 3.9 (3.8) kg in the intervention group, (p=0.56). HbA1c improved without difference between groups. Post-hoc multivariate analysis of all participants found that weight gain was independently associated with younger age, active smoking, and the magnitude of HbA1c reduction. A 1% decrease in HbA1c was associated with an increase of 0.94kg [95% Confidence Interval 0.47; 1.41], p<0.001.

CONCLUSIONS

Treatment intensification by insulin pump therapy in patients with type 2 diabetes is effective to improve glycaemic control. A gain of about 1 kg per 1% drop in HbA1c can be expected after insulin treatment intensification. This weight gain was not prevented by a home-base, individualized, 6-months lifestyle intervention program.

Weight cycling based on altered immune microenvironment as a result of metaflammation

As a result of the obesity epidemic, more people are concerned about losing weight; however, weight regain is common, leading to repeated weight loss and weight cycling. The health benefits of early weight loss are nullified by weight regain after weight cycling, which has much more severe metabolic consequences. Weight cycling alters body composition, resulting in faster fat recovery and slower muscle reconstruction. This evident fat accumulation, muscle loss, and ectopic fat deposition destroy the intestinal barrier, increase the permeability of the small intestinal epithelium, and cause the lipotoxicity of lipid metabolites and toxins to leak into extraintestinal tissues and circulation. It causes oxidative stress and hypoxia in local tissues and immune cell infiltration in various tissues, all contributing to the adaptation to this metabolic change. Immune cells transmit inflammatory responses in adipose and skeletal muscle tissue by secreting cytokines and adipokines, which mediate immune cell pathways and cause metaflammation and inefficient metabolic degradation. In this review, we focus on the regulatory function of the immunological microenvironment in the final metabolic outcome, with a particular emphasis on the cellular and molecular processes of local and systemic metaflammation induced by weight cycling-induced changes in body composition. Metaflammation in adipose and muscle tissues that is difficult to relieve may cause weight cycling. As this chronic low-grade inflammation spreads throughout the body, metabolic complications associated with weight cycling are triggered. Inhibiting the onset and progression of metabolic inflammation and enhancing the immune microenvironment of adipose and muscle tissues may be the first step in addressing weight cycling.

After the spotlight: are evidence-based recommendations for refeeding post-contest energy restriction available for physique athletes? A scoping review

Background: To date, there is limited consensus on post-contest recovery recommendations for natural physique athletes. The available literature emphasizes the negative consequences of extreme dieting associated with physique contests, yet offers only speculative suggestions to facilitate physiological recovery post-contest. This scoping review evaluates evidence-based recommendations for recovery in post-physique contests. Methods: The online search engines and databases Google Scholar, PubMed, and Scopus were searched systematically and 12 peer reviewed journal articles were included in the review. Results: Six key factors were identified that directly impacted on physiological recovery post-contest: (1) body composition, (2) recovery dietary intake, (3) resting metabolic rate (RMR) restoration, (4) endocrine measures recovery, (5) menstrual cycle recovery, and (6) psychological aspects of recovery. Conclusions: Three dietary strategies have been proposed to facilitate physiological recovery post-contest while bearing in mind body composition and future athlete outcomes; (1) a gradual increase in energy intake to maintenance requirements, (2) ad libitum eating, (3) an immediate return to maintenance energy requirements. Future research is required to determine the timeline in which full physiological recovery occurs post-contest and which strategies best support athlete health and performance during post-contest recovery.

Obesity Mediates the Effect of Past and Current Mental Health on Diabetes Treatment Outcomes

Background

Anxiety and depression (A&D) are common among patients with diabetes (DM). We assessed the mediatory effect of obesity on the pathway between past and current mental health (as measured by A&D) on self-care DM treatment adherence and DM treatment failure.

Methods

We used data collected in two rounds (2009-12, 2014-2018) of a population-based cohort study in Kerman, Iran (KERCADRS). By a random cluster sampling approach, 5900 residents of Kerman aged 15 to 75 yr were recruited to the study to measure demographic characteristics, body measures (to calculate BMI), adherence to DM treatment, and symptoms for A&D (Beck questionnaires). Fasting blood also collected for biochemical tests and glycemic control (as an indicator for treatment failure). We used path analysis and Structural Equation Modeling (SEM) for analysis.

Results

We analyzed data for 264 patients with diabetes who attended in both study rounds. While only 5.7% reported not adherence to DM treatment, 67.9% had diabetes treatment failure. Past mental health had a significant positive association with HbA1c (standard beta coefficient for total effect =0.148, P=0.044), of which 42% was indirect effect through obesity. Current mental health had a positive association with current no adherence to diabetes treatment (standard beta coefficient for total effect=0.077, P=0.001).

Conclusion

Our study showed an important indirect path from A&D to diabetes treatment failure outcome which mediated by obesity. Screening for A&D symptoms and treating those as well as obesity among patients with diabetes may improve glycemic control.

Association between weight-loss history and weight loss achieved in clinical obesity management: Retrospective chart review

OBJECTIVE

Weight history and its association with the weight loss achieved in a publicly funded clinical obesity management program were examined in 9348 patients.

METHODS

Weight history (frequency and magnitude of weight losses) was collected through questionnaires at enrollment, and weight change was assessed with retrospective electronic medical chart review.

RESULTS

The majority of patients reported developing overweight prior to the age of 40 years and having lost at least 4.5 kg (10 lb) of weight at least once in their lifetime. Those who had an earlier onset of overweight had a higher frequency of past weight loss and had more cumulative weight loss over their lifetime. In women, but not men, earlier age of overweight onset and lifetime weight loss were associated with modestly greater weight loss at the clinic.

CONCLUSIONS

Women with greater weight-loss history also have modestly greater weight loss at the obesity management clinic. Thus, successful long-term obesity management, particularly for women, may include a series of repeated attempts at weight loss that should not be viewed as failures but could be viewed instead as practice.

Weight management behaviours mediate the relationship between weight cycling, BMI and diet quality among US Army Soldiers

Weight cycling is prevalent in sports/professions with body composition standards, and has been associated with weight management behaviours that may contribute to suboptimal diet quality and weight gain. US Army Soldiers may be at increased risk of weight cycling relative to civilians due to mandated body composition standards. However, the relationship between weight cycling, weight management behaviours, BMI and diet quality among Soldiers is unknown. In this cross-sectional study, 575 Soldiers (89 % enlisted, 90 % male, 23 ± 4 years) at Army installations at Joint Base Elmendorf-Richardson, AK, Joint-Base Lewis McChord, WA, and Fort Campbell, KY completed questionnaires on food frequency, health-related behaviours and history of weight cycling (≥ 3 weight fluctuations ≥ 5 % body weight). Weight cycling was reported by 33 % of Soldiers. Those who reported weight cycling reported higher BMI (27 ± 4 v. 25 ± 3 kg/m², P < 0·001) and higher prevalence of engaging in weight management behaviours prior to body weight screening but did not report lower dietary quality (Healthy Eating Index-2015 (HEI) scores 59 ± 10 v 59 ± 11, P = 0·46) relative to those who did not report weight cycling. Results of mediation analyses suggested that weight cycling may affect BMI both directly (c' = 1·19, 95 % CI: 0·62, 1·75) and indirectly (ab = 0·45, 95 % CI: 0·19, 0·75), and HEI scores indirectly (ab = 0·69, 95 % CI: 0·20, 1·35) through the adoption of weight management behaviours. Weight cycling is common in Soldiers and is associated with higher BMI and higher prevalence of engaging in weight management behaviours that mediate associations between weight cycling, BMI and diet quality.

The association between diabetes and hypertension with the number and extent of weight cycles determined from 6 million participants

The purpose of this study was to elucidate the association between weight cycling and clinical outcomes such as type 2 diabetes and hypertension with differential effects of baseline age and obesity. Nationwide data from 6,132,569 healthy adults who underwent five or more health screenings between 2002 and 2011 were analyzed and followed until December 2019 for type 2 diabetes and hypertension. Weight cycling was defined as a change in body weight followed by another change in the opposite direction. Through the Cox proportional hazards model, the number and degree of weight cycles were positively associated with increased risk of type 2 diabetes and hypertension. The hazard ratios (HRs) of weight cycling for type 2 diabetes and hypertension were as high as 1.263 (1.213-1.315) and 1.175 (1.144-1.207) at two or more weight cycles of 10% of body weight (BW), respectively. The association was stronger for females, individuals with normal body weight/BMI, and older individuals. Weight cycling was significantly associated with an increased risk of adverse health outcomes and was stronger in individuals with normal BMI and females, indicating that these people should be informed about the potential risk of weight cycling.

The Minnesota Starvation Experiment and Force Feeding of Prisoners-Relying on Unethical Research to Justify the Unjustifiable

This article poses a response to one argument supporting the force feeding of political prisoners. This argument assumes that prisoners have moral autonomy and thus cannot be force fed in the early stages of their hunger strike. However, as their fasting progresses, their cognitive competence declines, and they are no longer autonomous. Since they are no longer autonomous, force feeding becomes justified. This article questions the recurrent citation of a paper in empirical support of the claim that hunger strike causes mental disorders or cognitive impairments. The paper, written by Daniel Fessler, partially relies on the Minnesota Starvation Experiment conducted in 1944 to 1945 for scientific support. Using widely accepted criteria for assessing the ethical acceptability of clinical research, we argue that the Minnesota Starvation Experiment had significant scientific shortcomings and is a case of unethical research. From this, we question the appropriateness of citing the Minnesota Starvation Experiment and consequently Fessler's paper. If Citing Fessler's paper becomes problematic, this particular argument for the force feeding of prisoners loses much of its strength.

Precision nutrition based on phenotypical traits and the (epi)genotype: nutrigenetic and nutrigenomic approaches for obesity care

PURPOSE OF REVIEW

The purpose of this article is to rationally review and critically appraise the current knowledge in the most relevant nongenetic and genetic factors influencing obesity predisposition. This information may be translated into the implementation of personalized nutrition approaches involving precision nutrigenetic and nutrigenomic strategies for obesity monitoring and weight management.

RECENT FINDINGS

The importance and influence of several nongenetic contributors to obesity onset and individual responses to weight-loss interventions have been highlighted including the role of age, sex or perinatal feeding and others related to an individual's lifestyle and modifiable. Nutrigenetic studies have analysed potential interactions between polymorphisms influencing energy homeostasis/body composition and dietary factors in relation to adiposity phenotypes and therapy responsiveness. A second approach comprises the Nutrigenomic analysis of gene expression modifications in response to the consumption of specific nutrients or dietary bioactive compounds, which may involve epigenetic mechanisms including deoxyribonucleic acid methylation and micro-ribonucleic acid expression profiles.

SUMMARY

Taken together, these findings encompass the importance of taking into account up-to-date advances in Nutrigenetic and Nutrigenomic hallmarks, globally analysing the risk of weight gain and related outcomes after following nutrition counselling, this contributing to improve obesity care considering phenotypical traits and the genetic make-up for precision obesity care.

Exercising for Insulin Sensitivity - Is There a Mechanistic Relationship With Quantitative Changes in Skeletal Muscle Mass?

Skeletal muscle (SM) tissue has been repetitively shown to play a major role in whole-body glucose homeostasis and overall metabolic health. Hence, SM hypertrophy through resistance training (RT) has been suggested to be favorable to glucose homeostasis in different populations, from young healthy to type 2 diabetic (T2D) individuals. While RT has been shown to contribute to improved metabolic health, including insulin sensitivity surrogates, in multiple studies, a universal understanding of a mechanistic explanation is currently lacking. Furthermore, exercised-improved glucose homeostasis and quantitative changes of SM mass have been hypothesized to be concurrent but not necessarily causally associated. With a straightforward focus on exercise interventions, this narrative review aims to highlight the current level of evidence of the impact of SM hypertrophy on glucose homeostasis, as well various mechanisms that are likely to explain those effects. These mechanistic insights could provide a strengthened rationale for future research assessing alternative RT strategies to the current classical modalities, such as low-load, high repetition RT or high-volume circuit-style RT, in metabolically impaired populations.

Weight cycling practices in sport: A risk factor for later obesity?

Weight cycling, repeated cycles of weight loss and weight regain over time, is commonplace amongst many population groups. Although the effect of weight cycling on future obesity and cardiometabolic risk is still hotly debated, evidence does indicate that individuals who were normal weight prior to weight cycling are more susceptible to its adverse consequences than those who were overweight or with obesity. Athletes, and particularly those who compete in the so-called weight-sensitive sports, are prone to dieting and weight cycling practice owing to the competitive advantage to be gained from manipulating their body weight. However, in comparison with the general population, athletes tend to be leaner and weight loss phases more rapid and superimposed on a background of a high level of physical activity. In this context, it can be questioned whether weight cycling in this subpopulation will indeed increase risk for future obesity. It is perhaps surprising that despite recognition that athletes commonly partake in weight cycling during their career, studies are scarce and firm conclusions regarding the effect of this practice on future cardiometabolic risk remain to be drawn. In this review, we examine weight cycling prevalence and strategies in athletes and the current evidence relating to its short- and long-term consequences. In addition, a conceptual framework relating the dynamics of weight loss and recovery to athlete characteristics will be discussed, highlighting the need for well-controlled, prospective studies in this specific subpopulation.

Ancel Keys: The legacy of a giant in physiology, nutrition, and public health

Ancel Keys, whose life spanned over 100 years (1904-2004), made a wealth of seminal scientific and public health contributions. As a physiologist, nutritionist, and public health scientist, he has left his mark on the 20th century by exploring different areas of physiology and nutrition, as well as by contributing to the understanding of basic public health issues. Among his major achievements one can mention in chronological order: studying adaptation to very high altitude, developing the K ration to enable the US military to survive with light but dense food, dissecting the physiology of starvation and nutritional rehabilitation to optimize recovery of functions, uncovering the link between serum cholesterol and heart disease, coordinating the first multi-country epidemiological longitudinal study in nutrition and health, coining the word "body mass index" (BMI), which he showed to be the best body weight index to predict body fat, and promoting the Mediterranean diet for a healthy life style. This review examines the historical events and scientific intrigues that have surrounded Ancel Keys's major classical studies that have ensured him a central place in the history of medical science.

Physiology of weight regain: Lessons from the classic Minnesota Starvation Experiment on human body composition regulation

Since its publication in 1950, the Biology of Human Starvation, which describes the classic longitudinal Minnesota Experiment of semistarvation and refeeding in healthy young men, has been the undisputed source of scientific reference about the impact of long-term food deprivation on human physiology and behavior. It has been a guide in developing famine and refugee relief programs for international agencies, in exploring the effects of food deprivation on the cognitive and social functioning of those with anorexia nervosa and bulimia nervosa, and in gaining insights into metabolic adaptations that undermine obesity therapy and cachexia rehabilitation. In more recent decades, the application of a systems approach to the analysis of its data on longitudinal changes in body composition, basal metabolic rate, and food intake during the 24 weeks of semistarvation and 20 weeks of refeeding has provided rare insights into the multitude of control systems that govern the regulation of body composition during weight regain. These have underscored an internal (autoregulatory) control of lean-fat partitioning (highly sensitive to initial adiposity), which operates during weight loss and weight regain and revealed the existence of feedback loops between changes in body composition and the control of food intake and adaptive thermogenesis for the purpose of accelerating the recovery of fat mass and fat-free mass. This paper highlights the general features and design of this grueling experiment of simulated famine that has allowed the unmasking of fundamental control systems in human body composition autoregulation. The integration of its outcomes constitutes the "famine reactions" that drive the normal physiology of weight regain and obesity relapse and provides a mechanistic "autoregulation-based" explanation of how dieting and weight cycling, transition to sedentarity, or developmental programming may predispose to obesity. It also provides a system physiology framework for research toward elucidating proteinstatic and adipostatic mechanisms that control hunger-appetite and adaptive thermogenesis, with major implications for a better understanding (and management) of cachexia, obesity, and cardiometabolic diseases.

How to provide a structured clinical assessment of a patient with overweight or obesity

With the increasing prevalence of overweight and obesity worldwide, there is a reciprocal increase in the global economic burden and ill-health from obesity-related chronic diseases. Primary healthcare services have a role to play in ensuring early detection of weight issues and in directing patients towards evidence-based care to slow this progression. Research shows that many people with obesity are motivated to lose weight and want their clinician to initiate a conversation about weight management and treatment options. However, this conversation rarely occurs and there is a significant delay in treatment, resulting in an increased burden on the individual, healthcare system and society. In this paper, the components and rationale for the clinical assessment of adult patients with overweight or obesity, including anthropometric measurements and pathology tests, are described. Recommendations to ascertain the potential factors influencing the development of obesity in the patient, such as lifestyle factors (diet and physical activity) and mental health, are also provided. The potential sequelae of obesity that may be present and the necessary assessments for diagnosis are also addressed. These assessments are vital to ensure the patient is referred to the appropriate allied health services and/or specialists.

Reduced metabolic efficiency in sedentary eucaloric conditions predicts greater weight regain in adults with obesity following sustained weight loss

Background

Successful long-term weight loss maintenance after caloric restriction (CR) is rarely achieved. Besides known metabolic, behavioral, and cognitive factors, 24-hour energy expenditure (24hEE) relative to body size (i.e., metabolic efficiency) might influence subsequent weight loss maintenance.

Methods

Eleven participants with obesity (BMI=39.0±8.7 kg/m², body fat=36.1±6.4%) had 24hEE measured in a whole-room indirect calorimeter during eucaloric conditions and weight stability prior to starting a 6-week inpatient CR study (50% of daily energy needs). Twenty-four-hour energy expenditure was adjusted via regression analysis for fat free mass (FFM) and fat mass (FM) by DXA. Body composition was reassessed at the end of CR and after 1-year follow-up. Free-living weight was assessed by monthly weight measurements during 12 months.

Results

After 6-week CR, participants lost 8.5±2.7% weight (FFM: −6.3±3.6 kg, FM: −3.4±1.2 kg) but regained 5.1±8.0% one year following CR, which was mostly due to FFM regain (+5.7±5.5 kg) and unchanged FM. A relatively higher 24hEE by 100 kcal/day prior to CR was associated with an average greater rate of weight regain by +0.3 kg/month during follow-up and a greater final weight regain by +5.1 kg after 1 year of follow-up.

Conclusion

These results suggest that reduced metabolic efficiency in 24hEE during eucaloric, sedentary conditions may predict greater weight regain after CR-induced weight loss.

Dietary Energy Partition: The Central Role of Glucose

Humans have developed effective survival mechanisms under conditions of nutrient (and energy) scarcity. Nevertheless, today, most humans face a quite different situation: excess of nutrients, especially those high in amino-nitrogen and energy (largely fat). The lack of mechanisms to prevent energy overload and the effective persistence of the mechanisms hoarding key nutrients such as amino acids has resulted in deep disorders of substrate handling. There is too often a massive untreatable accumulation of body fat in the presence of severe metabolic disorders of energy utilization and disposal, which become chronic and go much beyond the most obvious problems: diabetes, circulatory, renal and nervous disorders included loosely within the metabolic syndrome. We lack basic knowledge on diet nutrient dynamics at the tissue-cell metabolism level, and this adds to widely used medical procedures lacking sufficient scientific support, with limited or nil success. In the present longitudinal analysis of the fate of dietary nutrients, we have focused on glucose as an example of a largely unknown entity. Even most studies on hyper-energetic diets or their later consequences tend to ignore the critical role of carbohydrate (and nitrogen disposal) as (probably) the two main factors affecting the substrate partition and metabolism.