Obesity: a disease or a biological adaptation?

The role of philosophy and ethics at the edges of medicine

BACKGROUND

The edge metaphor is ubiquitous in describing the present situation in the world, and nowhere is this as clearly visible as in medicine. "The edge of medicine" has become the title of books, scholarly articles, media headlines, and lecture series and seems to be imbued with hype, hope, and aversion. In order better to understand what is at stake at "the edge of medicine" this article addresses three questions: What does "the edge of medicine" mean in contemporary debates on modern medicine? What are the challenges "on the edge of medicine" (in these various meanings of "on the edge")? How can philosophy and ethics contribute with addressing these challenges?

METHODS

Literature searches in PubMed and Google Scholar are used to identify uses of the phrase "the edge of medicine" while conventional content analysis is used to analyze meanings of and challenges with "the edge of medicine." These results are then investigated with respect to how philosophy and ethics can address the identified challenges.

RESULTS

The literature reveals that "the edge of medicine" has many meanings, such as: Border; Margin (of life); Frontier; Forefront; Fringes; Plunge (abyss); Brink (verge); Conflict; and Balancing. In general, the various meanings address four basic challenges: setting limits, keeping control, make meaning, and handling conflicts or aporias. The analysis of each of the meanings of "the edge of medicine" identifies a wide range of important and urgent tasks for the humanities in general, and for philosophy and ethics in particular: 1) clarifying concepts; 2) clarifying assumptions and premises of arguments, methods, advice, and decisions; 3) elaborate new concepts and new theories; 4) conceptualize and handle uncertainty, moral regret, and residue; 5) reveal "the emperor's new clothes;" 6) identify trends and reflect on their implications; 7) demarcation; and 8) reflecting on goodness in medicine.

CONCLUSION

The phrase "the edge of medicine" expresses a wide range of challenges for modern health care. Together with other disciplines philosophy and ethics can and should make crucial contributions at "the edge of medicine," which is where the future of human beings and societies is created and formed.

Triboelectric Nanogenerators for Therapeutic Electrical Stimulation

Current solutions developed for the purpose of in and on body (IOB) electrical stimulation (ES) lack autonomous qualities necessary for comfortable, practical, and self-dependent use. Consequently, recent focus has been placed on developing self-powered IOB therapeutic devices capable of generating therapeutic ES for human use. With the recent invention of the triboelectric nanogenerator (TENG), harnessing passive human biomechanical energy to develop self-powered systems has allowed for the introduction of novel therapeutic ES solutions. TENGs are especially effective at providing ES for IOB therapeutic systems given their bioconformability, low cost, simple manufacturability, and self-powering capabilities. Due to the key role of naturally induced electrical signals in many physiological functions, TENG-induced ES holds promise to provide a novel paradigm in therapeutic interventions. The aim here is to detail research on IOB TENG devices applied for ES-based therapy in the fields of regenerative medicine, neurology, rehabilitation, and pharmaceutical engineering. Furthermore, considering TENG-produced ES can be measured for sensing applications, this technology is paving the way to provide a fully autonomous personalized healthcare system, capable of IOB energy generation, sensing, and therapeutic intervention. Considering these grounds, it seems highly relevant to review TENG-ES research and applications, as they could constitute the foundation and future of personalized healthcare.

Elevated circulatory levels of leptin and resistin impair therapeutic efficacy of dacarbazine in melanoma under obese state

Background

Obesity is associated with increased risk, poor prognosis and outcome of therapy, in various cancers. Obesity-associated factors or adipokines, especially leptin and resistin, are purported to promote growth, survival, proliferation, and invasiveness of cancer cells. However, the mechanistic link between these adipokines and therapeutic response in malignancies is not clearly understood.

Methods

ob/ob and db/db mouse models were used in this study to evaluate the role of leptin and resistin towards the outcome of dacarbazine (DTIC) therapy in melanoma. Unique in vitro approaches were employed to complement in vivo findings by culturing melanoma cells in the serum collected from the experimental mice.

Results

Here, we have shown the role of important adipokines leptin and resistin in growth and the outcome of DTIC therapy in melanoma. Both leptin and resistin not only enhance proliferation of melanoma cells but also are involved in impairing the therapeutic efficacy of DTIC. Leptin and resistin treatment caused an increase in the protein levels of fatty acid synthase (FASN) and caveolin 1 (Cav-1) respectively, through their stabilization in A375 cells. Further, it was observed that leptin and resistin impaired the response of melanoma cells to DTIC via upregulation of heat shock protein 90 (Hsp90) and P-glycoprotein (P-gp) respectively.

Conclusion

These findings unraveled the involvement of adipokines (leptin and resistin) in melanoma progression, and more importantly, in the outcome of DTIC therapy.

Food addiction and obesity: unnecessary medicalization of hedonic overeating

The concept of addiction is loaded with connotations and is often used for its political as much as its medical utility. The scientific case for 'food addiction' as a clinical phenotype currently rests on its association with generic diagnostic criteria for substance-related disorders being applied to everyday foods and eating-related problems. This has fused the concept of obesity with addiction regardless of whether it fits the definition. The hedonic, or reward, system can account for the ingestion of foods and drugs, confirming that they share neural substrates that differentiate liking and wanting. These are normal processes that are recruited for natural homeostatic behaviours and can explain the phenomenon of hedonic overeating as a consequence of human motivation pushed to extremes by an obesogenic environment. Food addiction constitutes a medicalization of common eating behaviours, taking on the properties of a disease. The use of this medical language has implications for the way in which society views overeating and obesity.

The Relationship between Stress and Severe Obesity: A Case-Control Study

Background

Several etiological factors for obesity have been identified, whereas other factors related to obesity, such as stress, remain poorly understood. This study used psychiatric methods to examine the relationship between stress and obesity.

Methods

Matched study and control groups were established, and the female and male control subjects were selected separately by random sampling. The control subjects were matched with the case subjects with respect to place of residence, sex, age, date that a pension was granted, and occupation. Psychiatric and psychological methods were assessed using a questionnaire and statistical analyses.

Results

Psychiatric interviews indicated that stress was more prevalent in the study group than in the control group. Separation from parents was nearly significantly more frequently in the study group than in the control group. The questionnaire on coping mechanisms revealed that case subjects tended to resolve their problems in an active manner.

Conclusions

The aim of this case-control study was to examine the relationship between stress and obesity in individuals receiving a disability pension. We identified stress factors that affect the development of obesity. We believe our study is both necessary and important, as these findings provide valuable insight into the relationship between severe obesity and stress.

Obesity as a Socially Defined Disease: Philosophical Considerations and Implications for Policy and Care

Obesity has generated significant worries amongst health policy makers and has obtained increased attention in health care. Obesity is unanimously defined as a disease in the health care and health policy literature. However, there are pragmatic and not principled reasons for this. This warrants an analysis of obesity according to standard conceptions of disease in the literature of philosophy of medicine. According to theories and definitions of disease referring to (abnormal functioning of) internal processes, obesity is not a disease. Obesity undoubtedly can result in disease, making it a risk factor for disease, but not a disease per se. According to several social conceptions of disease, however, obesity clearly is a disease. Obesity can conflict with aesthetic, moral, or other social norms. Making obesity a "social disease" may very well be a wise health policy, assuring and improving population health, especially if we address the social determinants of obesity, such as the food supply and marketing system. However, applying biomedical solutions to social problems may also have severe side effects. It can result in medicalization and enhance stigmatization and discrimination of persons based on appearance or behavior. Approaching social problems with biomedical means may also serve commercial and professionals' interests more than the health and welfare of individuals; it may make quick fix medical solutions halt more sustainable structural solutions. This urges health insurers, health care professionals, and health policy makers to be cautious. Especially if we want to help and respect persons that we classify and treat as obese.

Prenatal phthalate exposure and 8-isoprostane among Mexican-American children with high prevalence of obesity

Oxidative stress has been linked to many obesity-related conditions among children including cardiovascular disease, diabetes mellitus and hypertension. Exposure to environmental chemicals such as phthalates, ubiquitously found in humans, may also generate reactive oxygen species and subsequent oxidative stress. We examined longitudinal changes of 8-isoprostane urinary concentrations, a validated biomarker of oxidative stress, and associations with maternal prenatal urinary concentrations of phthalate metabolites for 258 children at 5, 9 and 14 years of age participating in a birth cohort residing in an agricultural area in California. Phthalates are endocrine disruptors, and in utero exposure has been also linked to altered lipid metabolism, as well as adverse birth and neurodevelopmental outcomes. We found that median creatinine-corrected 8-isoprostane concentrations remained constant across all age groups and did not differ by sex. Total cholesterol, systolic and diastolic blood pressure were positively associated with 8-isoprostane in 14-year-old children. No associations were observed between 8-isoprostane and body mass index (BMI), BMI Z-score or waist circumference at any age. Concentrations of three metabolites of high molecular weight phthalates measured at 13 weeks of gestation (monobenzyl, monocarboxyoctyl and monocarboxynonyl phthalates) were negatively associated with 8-isoprostane concentrations among 9-year olds. However, at 14 years of age, isoprostane concentrations were positively associated with two other metabolites (mono(2-ethylhexyl) and mono(2-ethyl-5-carboxypentyl) phthalates) measured in early pregnancy. Longitudinal data on 8-isoprostane in this pediatric population with a high prevalence of obesity provides new insight on certain potential cardiometabolic risks of prenatal exposure to phthalates.

Relationship of serum carotenoid concentrations with allostatic load as a measure of chronic stress among middle-aged adults in the USA

OBJECTIVE

Chronic stress and repeated physiological attempts at stress adaptation may result in 'fatigue' and suboptimal performance of multiple physiological systems, i.e. allostatic load (AL). Although carotenoids have been linked with individual cardiovascular, metabolic and inflammatory biomarkers, little is known about the relationship of carotenoids with the multi-system biomarker measure of stress, AL. The present study examined the association of serum concentrations of carotenoids with AL among middle-aged adults.

DESIGN

Cross-sectional. AL score was calculated based on nine risk-rated indicators (systolic and diastolic blood pressure, pulse rate, total and HDL-cholesterol, glycosylated Hb, sex-specific waist-to-hip ratio, albumin and C-reactive protein).

SUBJECTS

Middle-aged (45-64 years, n 3387) men and women participants in the Third National Health and Nutrition Examination Survey, NHANES III (1988-1994).

RESULTS

Serum β-carotene concentration was inversely associated with high AL after adjusting for age, education, race/ethnicity, serum cotinine, alcohol consumption, physical activity and other carotenoids (α-carotene, β-cryptoxanthin, lycopene, lutein/zeaxanthin). Females in the lowest β-carotene quartile were 2·94 (95 % CI 1·74, 4·94) times and males 2·90 (95 % CI 1·43, 5·89) times as likely to have high AL, compared with peers in the highest quartile (P for linear trend 0·001 and 0·018 for females and males, respectively). Mean serum β-carotene concentrations were also inversely associated with the number of 'high-risk' AL components (P for linear trend <0·001 and 0·004 for females and males, respectively).

CONCLUSIONS

Our study adds to evidence linking low β-carotene levels with unfavourable health outcomes.

Trefoil factor family member 2 (Tff2) KO mice are protected from high-fat diet-induced obesity

INTRODUCTION

Trefoil factor family member 2 (Tff2) is a small gut peptide, mainly known for its protective and healing functions. As previously demonstrated, high-fat (HF) feeding can rapidly and specifically modulate Tff2 transcription in key tissues of mice, including the duodenum and mesenteric adipose tissue, therefore suggesting a novel role for this gene in energy balance.

DESIGN AND METHODS

To explore whether and how Tff2 can influence feeding behavior and energy metabolism, Tff2 knock-out (KO) mice were challenged with HF diet for 12 weeks, hence food and energy intakes, body composition, as well as energy excretion and serum lipid and hormonal levels were analyzed. Finally, energy efficiency was estimated.

RESULTS

Tff2 KO mice showed a greater appetite and higher energy intake compared to wild-type (WT). Consistently, they presented lower levels of serum leptin, and increased transcription of agouti-related protein (Agrp) in the hypothalamus. Though energy and triglyceride fecal excretion were augmented in Tff2 KO mice, digestible energy intake was superior. However, KO mice were finally protected from HF diet-induced obesity, and accumulated less weight and fat depots than WT animals, while keeping a normal lean mass. Energy efficiency was lower in HF-KO mice, while energy expenditure and locomotor activity were globally increased.

CONCLUSIONS

The present work demonstrates previously unsuspected roles for Tff2 and suggests it to be a mastermind in the control of energy balance and a promising therapeutic target for obesity.

Urinary F2-Isoprostanes Are Not Associated with Increased Risk of Type 2 Diabetes

OBJECTIVE

Free radicals have been implicated in the etiology of type 2 diabetes. Cross-sectional studies have demonstrated associations between oxidative damage and type 2 diabetes. However, no prospective data on this association are available.

RESEARCH METHODS AND PROCEDURES

A case control study was conducted within the prospective cohort of the Insulin Resistance Atherosclerosis Study: 26 cases who developed type 2 diabetes in the follow-up period and 26 controls who remained free of type 2 diabetes were randomly selected. Oxidative status was assessed by measuring 2,3-dinor-5,6-dihydro-15-F2t-isoprostane (F2-IsoPM) in baseline urine samples using gas chromatography/mass spectroscopy. Type 2 diabetes was defined by serial oral glucose tolerance tests and World Health Organization criteria.

RESULTS

Urinary F2-IsoPM varied between 0.18 and 2.60 ng/mg creatinine; 25th/50th/75th percentiles were 0.42, 0.60, and 0.89, respectively. A trend toward higher levels were observed in women and in persons with impaired glucose tolerance at baseline (p = 0.1). F2-IsoPM increased with BMI (r = 0.36, p = 0.01). After adjustment for age, gender, baseline impaired glucose tolerance status, and BMI, F2-IsoPM levels were inversely associated with development of type 2 diabetes: odds ratio = 0.32 (95% confidence interval, 0.12 to 0.81) for the difference between the 75th and 25th percentiles.

DISCUSSION

These results suggest that oxidative damage is not a cause of type 2 diabetes. Positive cross-sectional associations of F2-IsoPM with the risk factors for diabetes, BMI, and impaired glucose tolerance and inverse associations with development of type 2 diabetes indicate that F2-IsoPM might reflect a compensatory mechanism.

Obesity: a disease or a biological adaptation? An update

Obesity is characterized by the accumulation of excess body fat and can be conceptualized as the physical manifestation of chronic energy excess. An important challenge of today's world is that our so-called obesogenic environment is conducive to the consumption of energy and unfavourable to the expenditure of energy. The modern, computer-dependent, sleep-deprived, physically inactive humans live chronically stressed in a society of food abundance. From a physiological standpoint, the excess weight gain observed in prone individuals is perceived as a normal consequence to a changed environment rather than a pathological process. In other words, weight gain is a sign of our contemporary way of living or a 'collateral damage' in the physiological struggle against modernity. Additionally, substantial body fat loss can complicate appetite control, decrease energy expenditure to a greater extent than predicted, increase the proneness to hypoglycaemia and its related risk towards depressive symptoms, increase the plasma and tissue levels of persistent organic pollutants that promote hormone disruption and metabolic complications, all of which are adaptations that can increase the risk of weight regain. In contrast, body fat gain generally provides the opposite adaptations, emphasizing that obesity may realistically be perceived as an a priori biological adaptation for most individuals. Accordingly, prevention and treatment strategies for obesity should ideally target the main drivers or root causes of body fat gain in order to be able to improve the health of the population.

Peroxisome Proliferators-Activated Receptor (PPAR) Modulators and Metabolic Disorders

Overweight and obesity lead to an increased risk for metabolic disorders such as impaired glucose regulation/insulin resistance, dyslipidemia, and hypertension. Several molecular drug targets with potential to prevent or treat metabolic disorders have been revealed. Interestingly, the activation of peroxisome proliferator-activated receptor (PPAR), which belongs to the nuclear receptor superfamily, has many beneficial clinical effects. PPAR directly modulates gene expression by binding to a specific ligand. All PPAR subtypes (alpha, gamma, and sigma) are involved in glucose metabolism, lipid metabolism, and energy balance. PPAR agonists play an important role in therapeutic aspects of metabolic disorders. However, undesired effects of the existing PPAR agonists have been reported. A great deal of recent research has focused on the discovery of new PPAR modulators with more beneficial effects and more safety without producing undesired side effects. Herein, we briefly review the roles of PPAR in metabolic disorders, the effects of PPAR modulators in metabolic disorders, and the technologies with which to discover new PPAR modulators.

Well-being of obese individuals: therapeutic perspectives

The history of pharmacologic treatment of obesity is characterized by too much focus on efficacy and too little on safety, which has led to withdrawals of drugs from the market after serious adverse events. The development of new drug targets for the management of obesity will definitively need to address effects of the CNS and overall cardiovascular safety in the early stages in order to avoid the mistakes from the past. For instance, weight loss can increase the symptoms of depression and promote a state of psychobiological vulnerability favoring weight regain. Body-weight management should then seek a balance between the health benefits of weight loss and its potential risks, a ‘zone’ that is associated with an optimal psychobiological well-being.

Do all sedentary activities lead to weight gain: sleep does not

PURPOSE OF REVIEW

To discuss the benefits of having a good night's sleep for body weight stability.

RECENT FINDINGS

Experimental studies have shown that short-term partial sleep restriction decreases glucose tolerance, increases sympathetic tone, elevates cortisol concentrations, decreases the satiety hormone leptin, increases the appetite-stimulating hormone ghrelin, and increases hunger and appetite. Short sleep duration might increase the risk of becoming obese, because it does not allow the recovery of a hormonal profile facilitating appetite control. Lack of sleep could also lead to weight gain and obesity by increasing the time available for eating and by making the maintenance of a healthy lifestyle more difficult. Furthermore, the increased fatigue and tiredness associated with sleeping too little could lessen one's resolve to follow exercise regimens.

SUMMARY

Short sleep duration appears to be a novel and independent risk factor for obesity. With the growing prevalence of chronic sleep restriction, any causal association between reduced sleep and obesity would have substantial importance from a public health standpoint. Future research is needed to determine whether sleep extension in sleep-deprived obese individuals will influence appetite control and/or reduce the amount of body fat.

Physical activity plays an important role in body weight regulation

Emerging literature highlights the need to incorporate physical activity into every strategy intended to prevent weight gain as well as to maintain weight loss over time. Furthermore, physical activity should be part of any plan to lose weight. The stimulus of exercise provides valuable metabolic adaptations that improve energy and macronutrient balance regulation. A tight coupling between energy intake and energy expenditure has been documented at high levels of physical exercise, suggesting that exercise may improve appetite control. The regular practice of physical activity has also been reported to reduce the risk of stress-induced weight gain. A more personalized approach is recommended when planning exercise programs in a clinical weight loss setting in order to limit the compensatory changes associated to exercise-induced weight loss. With modern environment promoting overeating and sedentary behavior, there is an urgent need for a concerted action including legislative measures to promote healthy active living in order to curb the current epidemic of chronic diseases.

Obese reversal by a chronic energy restricted diet leaves an increased Arc NPY/AgRP, but no alteration in POMC/CART, mRNA expression in diet-induced obese mice

Weight regain after weight loss is a major hurdle for combating obesity. The aim of this study is to examine orexigenic and anorectic neuropeptides of the hypothalamic arcuate nucleus (Arc) in response to weight loss after chronic energy intake restriction. Thirty mice were fed with a high-fat diet for 8 weeks and then classified as diet-induced obese (DIO; n=10) or diet-resistant (DR; n=10) mice according to the highest and lowest body weight gainers. Five mice from DIO and DR groups were placed on an energy restricted diet or continued on their high-fat diet ad libitum for 6 weeks. An additional five mice were on a LF diet throughout the course of this study as controls. Results showed that a six-week energy restricted diet completely reversed the increased body weight, fat mass and leptin in the DIO mice to the levels of the LF and DR mice. Arc neuropeptide Y (NPY) and agouti-related protein (AgRP) mRNA expression in DIO mice after obesity reversal were significantly higher than DIO mice without obesity reversal (17%, 47%, both p<0.05), while the Arc pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) mRNA showed no difference. Both NPY and AgRP expression in DIO mice were negatively correlated with plasma leptin (R=-0.78, p<0.05; R=-0.72, p<0.05). In conclusion, while chronic energy restriction will lead to weight loss, it can up-regulate hypothalamic orexigenic peptides, which may be an important contributing factor to weight regain after a weight loss program from an energy restricted diet.

The glucostatic theory of appetite control and the risk of obesity and diabetes

More than 50 years ago, Jean Mayer proposed that changes in blood glucose concentrations or arteriovenous glucose differences are detected by glucoreceptors that affect energy intake. According to this theory, an increase in blood glucose concentrations results in increased feelings of satiety whereas a drop in blood glucose concentrations has the opposite effect. The pioneering work of Mayer has recently received support from our group as low glycemia has been shown to be linked with body weight gain prospectively and has been considered as a strong predictor of the amount of weight regained after weight loss. This state of mild hypoglycemia also predicts the increase in depressive symptoms with weight loss and a greater propensity to glucose intolerance and type 2 diabetes, particularly for individuals having short sleep durations. Furthermore, knowledge-based work has been shown to induce a significant increase in spontaneous energy intake being related to changes in glycemic control. In accordance with the glucostatic theory, this oriented review suggests that factors favoring a trend toward hypoglycemia and/or glucose instability might induce excess energy intake, overweight and impaired glucose tolerance. Data also raise the possibility that fat gain might be protective against mild hypoglycemia by providing compensation to the stimuli promoted by a modern environment.

About unsuspected potential determinants of obesity

The positive energy balance underlying obesity is generally attributed to factors exerting a direct measurable impact on energy intake or expenditure. Thus, sedentariness and (or) excess caloric intake represent the “Big Two” factors on which almost all the attention of health professionals is devoted in preventive and therapeutic programs for obesity. However, recent research reveals that other more discrete factors can also promote a positive energy balance and body fat gain. Accordingly, this paper documents the effects of low micronutrient intake, short sleep duration, knowledge-based work, and organochlorine compounds on components of energy balance and body composition. These effects aid in the understanding as to why modernity accentuates the risk of obesity. Furthermore, they also suggest that body fat gain is not only a problem, but also a solution in maintaining body homeostasis, i.e., a state of optimal body functionality, in the context of modernity and globalization.

Increase in depression symptoms with weight loss: association with glucose homeostasis and thyroid function

The purpose of this study was to assess the potential impact of weight loss up to a state of plateau on symptoms of depression. Eleven obese men (mean body mass index (BMI)=33.4 kg.m(-2), mean age=38 y) participated in this repeated-measures, within-subjects, clinical intervention. They were subjected to a weight-loss program that consisted of a supervised diet and exercise clinical intervention. The phases investigated were (i) baseline; (ii) after 5+/-1 kg loss of body mass (phase 1); (iii) after 10+/-1 kg weight loss (phase 2); and (iv) at resistance to further weight loss (plateau). At each phase of the weight-reducing program, glucose homeostasis markers were determined using an oral glucose tolerance test (OGTT). Serum thyroid-stimulating hormone (TSH), total triiodothyronine (T3), and free thyroxine (fT4) concentrations were also measured and the Beck Depression Inventory (BDI) was administered. The weight loss plateau occurred after 7.4+/-1.9 months of intervention and corresponded to a loss of 11.2% of initial body weight (93.9% of which was from fat stores). This amount of weight loss induced a significant decrease in resting metabolic rate (RMR) (p<0.05) and a significant increase in desire to eat (p<0.05) and in depression symptoms (p<0.01) compared with baseline. Intriguingly, the glucose area below fasting values (GABF) at plateau was significantly higher as compared with other phases of the program (p<0.01). We found a strong negative correlation (r=-0.77, p<0.01) between the change in glucose concentrations at 180 min of the OGTT and the change in BDI scores between plateau and baseline values. Similarly, highly significant relationships were found between the change in T3 or fT4 concentrations and the change in BDI scores (r=-0.71 and r=-0.68, respectively; p<0.01). Weight loss until plateauing is associated with a trend toward hypoglycemia at the end of the oral glucose challenge and with a decrease in T3 and fT4 levels. These physiological changes are shown to be highly linked with the increase in depression symptoms observed at plateau. Taken together, these data emphasize the relevance of caution and reasonable objectives when prescribing a weight reduction program to obese individuals.

Psychobiological effects observed in obese men experiencing body weight loss plateau

Our objective was to investigate the psychobiological impact associated with resistance to further weight loss in obese men. Anthropometric and body composition measurements, resting metabolic rate (RMR) measurement, appetite sensation markers, and three questionnaires [Short Form-36 Health Survey (SF-36), Three-Factor Eating Questionnaire (TFEQ), and Beck Depression Inventory (BDI)] were assessed at baseline and after 1 month of body weight loss plateau induced by a supervised diet and exercise clinical intervention in 11 obese men. The weight loss plateau corresponded to 11.2% of initial body weight (93.9% from fat stores). However, this amount of weight loss induced a significant decrease in RMR (P <.05) and a significant increase in hunger (P <.05) and desire to eat (P <.05). Using the SF-36 Health Survey, physical and mental health were shown to be unchanged at plateau as compared to baseline. The TFEQ showed that cognitive dietary restraint increased (P <.001) compared to baseline. Finally, depression risk as measured by the BDI significantly increased at plateau (P <.01) compared to baseline. Weight loss until resistance to further weight loss may be detrimental for some psychobiological variables including depression, which emphasizes the relevance of caution and reasonable objectives when prescribing a weight reduction program for obese individuals.

Management of antipsychotic-induced weight gain: prospective naturalistic study of the effectiveness of a supervised exercise programme

OBJECTIVE

To determine the potential effectiveness of a behavioural weight control programme including physical exercise in the prevention of antipsychotic-induced weight gain and associated comorbid conditions in outpatients with schizophrenia and mood disorders.

METHODS

A prospective, comparative, open and naturalistic study was carried out for a total of 110 patients with schizophrenia, schizoaffective or bipolar disorders (DSM-IV), on treatment with atypical antipsychotics. Of these, 59 patients participated in an 18 month weight control programme that included an educational activity about dietary and physical activity counselling as well as a structured, supervised, facility-based exercise programme. The control group consisted of 51 patients with the same baseline characteristics who did not receive the clinical programme. Anthropometric measurements, plasma lipid-lipoprotein profile, and fasting plasma glucose concentrations were assessed at 11 time-points over the study. In addition, serum concentrations of prolactin, thyrotropin-stimulating hormone (TSH), and glycated haemoglobin (HbA1c) were assessed at four time-points. Finally, the Clinical Global Impression scale (CGI), the Brief Psychiatric Rating Scale (BPRS) and the Short Form (SF)-36 Health Survey were used.

RESULTS

The adherence rate of patients was 85%, both in the active and in the control group. Whereas the control group experienced a significant increase in bodyweight (4.1%), body mass index (BMI; 5.5%) and waist circumference (WC; 4.2%), the active group significantly reduced their bodyweight (-3.5%), BMI (-4.4%), and WC (-4.6%) at the study end-point. In addition, a significant increase in low-density lipoprotein (LDL)-cholesterol (14.8%) and in triglyceride concentrations (12.3%) was observed at month 18 in the control group. In contrast, high-density lipoprotein-cholesterol (HDL) significantly increased (21.4%), and LDL cholesterol (-13.7%), triglycerides (-26.2%), total cholesterol (-12.1%), fasting glucose concentrations (-12.0%), and HbA1c (-11.4%) significantly decreased compared to baseline in the active group. No significant changes were observed regarding serum concentrations of prolactin and TSH during the study. In regard to the changes observed in psychological measures, no between-group differences were seen in the clinical ratings of CGI and BPRS. However, the SF-36 showed that physical health was improved only for subjects in the active group at months 12 and 18 compared to baseline (p<0.05), and mental health was significantly improved for both groups at months 12 and 18 compared to baseline.

CONCLUSION

Bodyweight and metabolic risk profile in patients receiving atypical antipsychotic medications can be effectively managed with a weight control programme including physical activity.

Metabolic and behavioral vulnerability related to weight regain in reduced-obese men might be prevented by an adequate diet–exercise intervention

The aim of this pilot study was to determine whether it was possible to prevent the metabolic and behavioral vulnerability related to weight regain generally observed in a reduced-obese state with a supervised diet-exercise clinical intervention. In this regard, the anthropometric and physiological effects of a body weight loss program were studied in 11 obese men and the impact of weight loss on appetite was measured by visual analogue scales (VAS) and by the use of a standardized buffet-type meal. All the measurements were assessed at the beginning of the intervention (baseline), after 5+/-1 kg body weight loss (Phase 1) and after 10+/-1 kg body weight loss (Phase 2). In Phase 1 and Phase 2, respectively, the diet-exercise intervention significantly reduced fat mass, waist circumference, fasting insulin and glucose, resting heart rate, and resting systolic and diastolic blood pressures. The diet-exercise intervention also preserved fat-free mass, resting metabolic rate, resting respiratory quotient, and immune function. No significant difference was observed in appetite sensations between the three time points, either measured with VAS in the fasting state or with the satiety quotient (SQ) calculation. Thus, this study provides evidence that obesity can be managed by adequate and specific lifestyle changes leading to clinical benefits while avoiding side effects potentially promoting an increase in energy intake and body weight relapse.

Appetite control after weight loss: what is the role of bloodborne peptides?

The literature presented in this paper argues that our limited ability to maintain energy balance in a weight-reduced state is the product of our difficulty in compensating for the weight loss-induced reduction in total energy expenditure. The end result, translated into the overwhelming complexity of preserving long-term weight loss, is presented as being a consequence of compromised appetite control. Given the present-day food landscape and the resultant susceptibility to passive overconsumption, the focus of this review will be on the peripheral (“bottom-up”) signals (leptin, PYY, ghrelin, and GLP-1) and the evidence highlighting their influence on feeding behaviour. As we continue studying paradigms of body mass reduction, specifically the data emerging from patients of bariatric surgery, it is becoming clearer that counter-regulatory adaptations, possibly through down-(leptin, PYY, and GLP-1) or upregulation (ghrelin) of peptides, have an impact on energy balance. In itself, food deprivation influences some of the peptides that ultimately provide the physiological input for the overt expression of feeding behaviour; these peripheral adaptations are expected to serve as feeding cues — cues that, in the end, can serve to compromise the maintenance of energy balance. In a potentially novel intervention to increase compliance to long-term reductions in energy intake, it is proposed that manipulating the pattern of food intake to favourably alter the profile of gastrointestinal peptides would lead to better dietary control.

Arabinoxylan consumption decreases postprandial serum glucose, serum insulin and plasma total ghrelin response in subjects with impaired glucose tolerance

OBJECTIVE

Arabinoxylan (AX) consumption is associated with metabolic improvement during diabetes and with modulation of ghrelin, an orexigenic gut hormone. The effect of AX consumption on ghrelin secretion in disturbed metabolic states is unknown. Therefore, we investigated the postprandial responses to AX consumption of serum glucose, insulin and triglycerides and plasma total and acylated ghrelin in subjects with impaired glucose tolerance (IGT).

DESIGN

Randomized, single-blind, controlled, crossover intervention trial.

SUBJECTS

Seven female and four male adults with IGT, aged 55.5 years, and body mass index (BMI) 30.1 kg/m(2).

INTERVENTION

Subjects received either placebo or 15 g AX supplement for 6 weeks with a 6-week washout period in-between.

MAIN OUTCOME MEASUREMENTS

Postprandial responses of serum glucose, insulin and triglycerides, and plasma total and acylated ghrelin after a liquid meal challenge test (LMCT) measured at the beginning and at the end of the dietary intervention at -20, -5, 0, 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 min.

RESULTS

After LMCT, AX consumption resulted in lower postprandial responses in serum glucose, insulin and triglycerides (P<0.05). Compared to placebo, total plasma ghrelin was also reduced by 42+/-8 pg/ml (P<0.001) after AX consumption with no difference in plasma acylated ghrelin.

CONCLUSION

AX consumption improved postprandial metabolic responses after an LMCT in subjects with IGT and reduced total ghrelin response. However, acylated ghrelin responses were unchanged, suggesting that the acylated ghrelin-mediated orexigenic regulation is not improved as only total plasma ghrelin decreased.

L'obésité : origines et conséquences d'une épidémie

Obesity is a chronic disease with serious health consequences. Initial weight gain is related to behavioural and environmental factors acting on a biological (mainly genetic) predisposition. The evolution of the disease is characterized by the development of an inflammatory organ disease that involves the adipocytes and other adipose tissue components. These alterations lead to various clinical complications and to a progressive resistance to diet effects. The treatment of obesity must be adapted to the stage of development of the disease and to the prevalent complications.

Body cell mass measured by total body potassium in normal-weight and obese men and women

OBJECTIVE

Total body potassium (TBK) concentration is linearly correlated with the size of the body cell mass (BCM). The aim of this study was to compare BCM in normal-weight and obese individuals.

METHODS

271 individuals (207 males, 64 females), 20 to 67 years of age, participated in this study. Subjects were separated by body mass index (BMI): BMI < 25 kg/m(2) (BMI-L) and BMI > 25 kg/m(2) (BMI-H). (40)K was assessed using a whole-body counter and BCM was calculated.

RESULTS

BCM and TBK were significantly greater in men, with a trend to be greater in women in BMI-H compared to men in BMI-L. TBK/body weight was significantly lower, while TBK/height was significantly greater for men and women in BMI-H compared to men and women in BMI-L. Fat-free mass (FFM) was significantly greater for men in BMI-H, with no significant differences in FFM between the two groups of women.

CONCLUSIONS

The healthy obese subjects in the present study had a greater BCM than the non-obese subjects. These results indicate that it is important to assess BCM in obese individuals because it could influence the type of weight loss regimen that will be used in order to preserve BCM.

Benzo[a]pyrene impairs beta-adrenergic stimulation of adipose tissue lipolysis and causes weight gain in mice. A novel molecular mechanism of toxicity for a common food pollutant

Benzo[a]pyrene (B[a]P) is a common food pollutant that causes DNA adduct formation and is carcinogenic. The report of a positive correlation between human plasma B[a]P levels and body mass index, together with B[a]P's lipophilicity, led us to test for possible adverse effects of B[a]P on adipose tissue. In ex vivo experiments using primary murine adipocytes, B[a]P rapidly (within minutes) and directly inhibited epinephrine-induced lipolysis (up to 75%) in a dose-dependent manner. Half-maximum inhibition was obtained with a B[a]P concentration of 0.9 mg.L(-1) (3.5 microm). Lipolysis induced by beta(1)-, beta(2)- and beta(3)-adrenoreceptor-specific agonists, as well as ACTH, were also significantly inhibited by B[a]P, whereas forskolin-induced lipolysis was not B[a]P-sensitive. Similar inhibition of catecholamine-induced lipolysis by B[a]P was also seen in isolated human adipocytes; half-maximum inhibition of lipolysis was achieved with a B[a]P concentration of 0.02 mg.L(-1) (0.08 microm). In vivo treatment of C57Bl/6J mice with 0.4 mg.kg(-1) B[a]P inhibited epinephrine-induced release of free fatty acids by 70%. Chronic exposure of mice to B[a]P (0.5 mg.kg(-1) injected i.p. every 48 h) for 15 days also decreased lipolytic response to epinephrine and induced a 43% higher weight gain compared with controls (B[a]P: 2.23 +/- 0.12 g versus control: 1.56 +/- 0.18 g, P < 0.01) due to increased fat mass. The weight gain occurred consistently without detectable changes in food intake. These results reveal a novel molecular mechanism of toxicity for the environmental pollutant B[a]P and introduce the notion that chronic exposure of human population to B[a]P and possibly other polycyclic aromatic hydrocarbons could have an impact on metabolic disorders, such as obesity.

Psychobiological impact of a progressive weight loss program in obese men

Psychobiological effects associated with a progressive body weight loss may help to improve the understanding of psychological barriers to weight loss. We hypothesized that a moderate body weight loss (about 10% of initial body weight) is accompanied with some negative psychological impact. Four questionnaires [SF-36 Health Survey, Three-Factor Eating Questionnaire (TFEQ), Beck Depression Inventory (BDI) and Pittsburgh Sleep Quality Index (PSQI)] were administered at each phase of a body weight loss program that consisted of a supervised diet and exercise clinical intervention to 11 obese men (mean BMI = 33.4 kg/m(2), mean age = 38 yr). The three phases investigated were: 1) at the beginning of the intervention (baseline); 2) after 5 +/- 1 kg body weight loss (Phase 1); and 3) after 10 +/- 1 kg body weight loss (Phase 2). Using the SF-36 Health Survey, physical and mental health were shown to be significantly improved at Phase 1 (p < 0.05). The TFEQ showed that cognitive dietary restraint increased (p < 0.001), and both disinhibition (p < 0.05) and susceptibility to hunger (p < 0.05) were significantly reduced at both Phase 1 and 2 compared to baseline. Depression as measured by the BDI significantly increased at Phase 2 (p < 0.05) compared to baseline and Phase 1. However, the mean BDI scores observed remained below the cut-off point for likely clinical significance. Finally, the PSQI showed that sleep quality was significantly improved at Phase 1 compared to baseline (p < 0.01). Altogether, these results suggest that a substantial improvement in the psychobiological profile occurs with a 5-kg weight loss (Phase 1) but that with additional weight loss (Phase 2) a small, but significant increase in depression occurred and seems to be associated with the increase in rigid restraint of eating. However, prospective studies with a larger sample are needed to confirm and deepen these results.

The seduction of general practice and illegitimate birth of an expanded role in population health care

To reduce health inequalities and improve quality in health care, health policy initiatives in countries including New Zealand and the United Kingdom are expecting general practice to share responsibilities for a population approach to health care. This is giving increased emphasis to preventative care, including health promotion. Reasoned debate on this policy is overdue, not least in New Zealand, where clinicians within general practice appear to have been seduced by the lack of clarity in health policy into accepting this policy without question. They appear to disregard implications of the policy for redefining the nature and scope of their discipline (and of public health), including their own role as providers of personal care. This paper suggests that a population health approach is inappropriate in general practice when this approach weakens personal care and involves health promotion activity of unknown safety and effectiveness. The example of intentional weight loss to reduce overweight is used to illustrate these issues. We argue for a restricted range of general practice services.

Is the insulin resistance syndrome the price to be paid to achieve body weight stability?

The insulin resistance syndrome represents a metabolic state in which hyperinsulinemia and/or insulin resistance constitute the platform underlying the development of metabolic complications and related diseases such as diabetes and coronary heart disease. As described in this paper, these insulin-related changes are also involved in the regulation of energy balance and contribute to the recovery of body weight stability in a context of long-term positive energy balance. Under conditions of negative energy balance such as obesity treatment, this connection has a high clinical relevance. In this regard, relevant literature as well as the reanalysis of previously published data suggest that the beneficial effect of weight loss on insulin-related changes in glycemia cannot be disassociated from the relationship between changes in plasma insulin and those in resting energy expenditure. In clinical terms, this suggests that the beneficial effect of weight loss on components of the insulin resistance syndrome could be related to the development of a state of physiological vulnerability that complicates the control of body weight. This poses a major challenge to health professionals who then have to manage obesity treatment as the search for a compromise between the beneficial and potentially detrimental effects of weight loss on insulinemia and insulin sensitivity. This also reinforces the relevance to adhere to healthy diet and physical activity habits in order to maintain body weight stability rather than relying on the overuse of regulatory systems soliciting the effects of hyperinsulinemia on the control of energy intake and expenditure.

Histoire naturelle des obésités

Obesity is a chronic disease. At the initial phase, behavioral and environmental factors play a key role in the constitution of adipose tIssue excess. Progressively biological alterations of adipose tIssue metabolism lead to some degree of irreversibility of the disease and contribute to the development of its metabolic and cardio-vascular complications.

Should we recommend low-fat diets for obesity?

Dietary fat intake has been blamed for the increase in adiposity and has led to a worldwide effort to decrease the amount of fat in the diet. However, the comparative efficacy of this approach is debatable. Whilst short-term dietary intervention studies show that low-fat diets lead to weight loss in both healthy and overweight individuals, it is less clear if a reduction in fat intake is more efficacious than other dietary restrictions in the long term. The purpose of this systematic review was to determine the effectiveness of low-fat diets in achieving sustained weight loss when used for the express purpose of weight loss in obese or overweight people. A comprehensive search identified six studies that fulfilled our criteria for inclusion (randomized controlled trial, participants either overweight or obese, comparison of a low-fat diet with another type of weight-reducing diet, follow-up period that was at least 6 months in duration and inclusion of participants 18 years or older without serious disease). There were a total of 594 participants in the six trials. The duration of the intervention varied from 3 to 18 months with follow-up from 6 to 18 months. There were no significant differences between low-fat diets and other weight-reducing diets in terms of sustained weight loss. Furthermore, the overall weight loss at the 12-18-month follow-up in all studies was very small (2-4 kg). In overweight or obese individuals who are dieting for the purpose of weight reduction, low-fat diets are as efficacious as other weight-reducing diets for achieving sustained weight loss, but not more so.

Energy balance and pollution by organochlorines and polychlorinated biphenyls

Organochlorines are fat-soluble chemical compounds resistant to degradation, so they are stored in the adipose tissue of practically every organism on the planet, including humans. Accumulation of these compounds in the body seems to be related to fat mass, obese individuals having a higher plasma organochlorine concentration than lean subjects. During body weight loss, lipid mobilization and a decrease in fat mass result in increased concentrations of organochlorines in plasma and adipose tissue. Organochlorines may have adverse health effects. For example, they have been associated with altered immune and thyroid functions and with some types of cancer. As these compounds may reach their target organs whilst in the circulation, their increase in plasma during weight loss might be associated with some physiological changes occurring during weight loss. Relationships have indeed been reported among weight loss-induced increase in plasma organochlorine concentration and decreased triiodothyronine (T3) concentration, resting metabolic rate, and skeletal muscle markers for fat oxidation. Although further studies are needed to assess the causality of these relationships, they raise concern about some potential undesirable effects of weight loss. Indeed, the effects of organochlorines on energy balance could complicate body weight loss and even favour weight regain. These notions lend support for weight-loss strategies favouring a moderate weight loss, which would reduce risks for cardiovascular diseases, diabetes and hypertension, without resulting in a substantial release of organochlorines.

Is obesity a disease?

BACKGROUND

There is disagreement about whether obesity should be considered a disease, as can be seen by inconsistent usage and the advocacy of conflicting views in popular and scholarly articles. However, neither writers who refer to obesity as a disease nor those who question whether it is a disease have generally provided a definition of disease and then offered evidence that obesity does or does not fit the definition.

METHOD

The characteristics of obesity were examined to determine whether they fit the common and recurring elements of definitions of disease taken from a sample of authoritative English language dictionaries.

FINDINGS AND INTERPRETATIONS

Obesity, defined as a body mass index (BMI, kg/m(2)) or percentage body fat in excess of some cut-off value, though clearly a threat to health and longevity, lacks a universal concomitant group of symptoms or signs and the impairment of function which characterize disease according to traditional definitions. While it might nevertheless be possible to achieve a social consensus that it is a disease despite its failure to fit traditional models of disease, the merits of such a goal are questionable. Labeling obesity a disease may be expedient but it is not a necessary step in a campaign to combat obesity and it may be interpreted as self-serving advocacy without a sound scientific basis.

Obesity treatment with a progressive clinical tri-therapy combining sibutramine and a supervised diet--exercise intervention

OBJECTIVE

: Sibutramine favors a negative energy balance and also has the potential to increase heart rate and blood pressure. We investigated if a progressive supervised sibutramine--diet--exercise clinical intervention could increase the body weight loss previously reported while minimizing the potential cardiostimulatory effects of this drug.

DESIGN AND SUBJECTS

: The tri-therapy intervention was divided into two phases of 6 weeks each in which sibutramine (10 mg) was taken once daily by eight obese men (body mass index (BMI) between 30 and 40 kg/m(2)). Part A consisted of a dietary follow-up with an energy restriction, whereas in part B an aerobic exercise program combined with a low-fat diet was introduced. Systolic (SBP) and diastolic (DBP) blood pressure, resting heart rate (RHR) and body weight were measured every 2 weeks while body density, resting metabolic rate (RMR) and respiratory quotient (RQ) were determined before and after the intervention.

RESULTS

: This clinical intervention produced a substantial body weight loss (-10.7 kg, P<0.01) which was about twice as much as other 12-week studies. In part A, both RHR (+4 beats/min) and DBP (+5 mmHg, P<0.01) were increased. However, after part B, RHR (-8 beats/min, P=0.02) and DBP (-3 mmHg, P<0.01) were significantly decreased. RMR was decreased at the end of the program but this effect did not persist after adjustments for fat-free mass. RQ was also reduced (-0.05, P<0.01) following the clinical tri-therapy.

CONCLUSION

: In conclusion, these observations suggest that this clinical tri-therapy favored a satisfactory benefit--risk profile since it enhanced weight loss without inducing increases in heart rate and blood pressure or detrimental changes in RMR and substrate oxidation.