Psychobiological effects observed in obese men experiencing body weight loss plateau

Effects of duration of uninterrupted fast in weekly intermittent fasting: Comparison of an 82-week 5:2 case report to an isocaloric modified 4:3 protocol

Intermittent fasting (IF) approach for weight loss obviates the inconvenience of calorie counting of daily caloric restriction (DCR). It tests IF ability to better counteract a metabolic defense mechanism (MDM) than DCR. MDM obstructs weight loss and facilitates weight regain possibly by increasing hunger and efficiency of exercise energy expenditure (EEf), and by reducing resting metabolic rate (RMR) and physical activity (PA). A knowledge gap exists about whether the duration of weekly uninterrupted fasts (UFs), where the IF protocols are isocaloric, mitigate the MDM. This study compares two IF protocols that have the same weekly number of hours of fast (108) and free access to food (60), but which differ in the duration of UF. An 82-week case report was conducted with twice-weekly near-absolute 36-hour fasts on non-consecutive days (5:2-NC) and compared to ten studies with a 20-hour UF on three non-consecutive days (4:3-NC) modified through provision of a 500-600 kcal meal on fasting days. The large meal raised insulin concentration for 4 hours and reduced the UF to 8 hours followed by 12 nocturnal hours of fasting. The hypotheses were that (1) because of their matched F/E ratio, the rates of weight and fat losses will be similar in both protocols, and (2) because of its longer UF period, hunger will be higher and RMR and voluntary physical activity lower, in 5:8-NC than in M4:3-NC protocol,. The main differences between the two protocols were, (1) slower rates of weight and fat losses, (2) lower sensation of hunger and substantial decline in fullness, no change in RMR and physical activity, and 2.5 times higher post-fast concentration of the ketone body beta-hydroxybutyrate (BHB) in 8:2-NC compared to M4:3-NC protocol. Absence of increased hunger and the variability of the rate of weight loss in 5:2-NC protocol, plus increased EEf in one M4:3-NC study suggest that IF does not curtail MDM, but shortened UF period in M4:3-NC reduces elicitation of BHB. Thus, the addition of a large meal on fasting days is unnecessary for prevention of hunger and is counterproductive for increases in BHB and its potential health benefits.

The Fasting and Shifted Timing (FAST) of Eating Study: A pilot feasibility randomized crossover intervention assessing the acceptability of three different fasting diet approaches

BACKGROUND AND AIMS

The aim of this study is to assess the acceptability of following three different fasting protocols [Early Time-restricted Feeding (eTRF; eating majority of kcals before 5pm), Time-restricted Feeding (TRF; restricting feeding window to 8 h/d), or Alternate Day Fasting (ADF; complete fasting every other day)].

METHODS

In this remotely delivered six-week crossover intervention, participants were randomly assigned to follow either an eTRF, TRF, or ADF diet for one week, followed by a one-week washout period. Participants followed all three diets and completed questionnaires assessing self-reported weight, energy intake, dietary acceptability (Food Acceptability Questionnaire), and facilitators and barriers to adhering to each diet. Differences in main outcomes (e.g., dietary acceptability and weight loss) were assessed via repeated measures ANOVA.

RESULTS

A total of 32 of participants began the study (mean BMI of 32.6 ± 6.0 kg/m²). There were no differences in kcals or weight loss among the three diets. Dietary acceptability was higher on the TRF diet (54.1 ± 8.2) than the eTRF (50.2 ± 6.6, p = 0.02) or ADF (48.0 ± 7.9, p = 0.004) diets. The majority of participants (71%) indicated the TRF diet was the easiest to follow and 75% said that ADF was the most difficult. Participants cited having a mobile app to track their diet and being provided with menu plans would help facilitate adherence with their diets.

CONCLUSIONS

This study found that acceptability was highest for an TRF diet and lowest for ADF, with no differences in weight loss or change in energy intake among the TRF, ADF, or eTRF groups.

CLINICAL TRIALS

GOV IDENTIFIER

NCT04527952.

The Impact of Restrictive and Non-restrictive Dietary Weight Loss Interventions on Neurobehavioral Factors Related to Body Weight Control: the Gaps and Challenges

PURPOSE OF REVIEW

Restrictive diets, such as low-calorie diets, are difficult to maintain in the long term. For this reason, their popularity has decreased compared to non-restrictive approaches, which instead promote healthy eating strategies. Since both strategies may entail different neurobiological mechanisms, this review will examine the current evidence on the effects of restrictive and non-restrictive interventions on neurobehavioral factors.

RECENT FINDINGS

Restrictive diets appear to improve eating behaviors, and the evidence reviewed argues against the notion that they may worsen the severity of binge eating. Moreover, they may lead to short-term changes in brain structure and improvements in cerebrovascular markers which, in turn, could impact eating behaviors. Non-restrictive interventions may have a positive effect on weight management and eating behaviors. However, evidence of their neural effects is scarce. Small sample sizes, short follow-ups, and the absence of control groups are limitations of the studies targeting both interventions. Rigorous long-term randomized studies are needed to examine the neurobehavioral effects of restrictive and non-restrictive approaches.

Associations between Fasting Duration, Timing of First and Last Meal, and Cardiometabolic Endpoints in the National Health and Nutrition Examination Survey

Background: Research indicates potential cardiometabolic benefits of energy consumption earlier in the day. This study examined the association between fasting duration, timing of first and last meals, and cardiometabolic endpoints using data from the National Health and Nutrition Examination Survey (NHANES). Methods: Cross-sectional data from NHANES (2005–2016) were utilized. Diet was obtained from one to two 24-h dietary recalls to characterize nighttime fasting duration and timing of first and last meal. Blood samples were obtained for characterization of C-reactive protein (CRP); glycosylated hemoglobin (HbA1c %); insulin; glucose; and high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total cholesterol. Survey design procedures for adjusted linear and logistic regression were performed. Results: Every one-hour increase in nighttime fasting duration was associated with a significantly higher insulin and CRP, and lower HDL. Every one-hour increase in timing of the last meal of the day was statistically significantly associated with higher HbA1c and lower LDL. Every one-hour increase in first mealtime was associated with higher CRP (β = 0.044, p = 0.0106), insulin (β = 0.429, p < 0.01), and glucose (β = 0.662, p < 0.01), and lower HDL (β = −0.377, p < 0.01). Conclusion: In this large public health dataset, evidence for the beneficial effect of starting energy consumption earlier in the day on cardiometabolic endpoints was observed.

How Does Fat Mass Change in the First Year After Bariatric Surgery? A Systemic Review and Meta-Analysis

This systematic review and meta-analysis investigated the time-course effect of different type of bariatric surgeries (BS) up to 1 year post-surgery on fat mass (FM) and body fat percentage (BFP) in patients with morbid obesity. We searched PubMed, Scopus, EMBASE, ISI web of science, and Cochrane databases from October 2002 until May 2020 with no restriction in the English language, to find studies examining the effect of BS on FM (kg) and BFP (%) in morbid obese patients. Meta-analysis of 103 studies carried out on data of 18,166 and 14,575 morbid obese patients following BS, showed that BS was associated with a substantial decrease in FM and BFP, respectively, in 1 month (- 8.17 kg [95% CI - 9.07, - 7.27] and - 1.51% [95% CI - 2.56, - 0.46]), 3 months (- 15.75 [95% CI - 17.49, - 14.0] and - 4.90 [95% CI - 5.97, - 3.83]), 6 months (- 22.51 [95% CI - 23.93, - 21.09] and - 8.56% [95% CI - 9.63, - 7.49]), and 12 months (- 29.69 [95% CI - 31.3, - 28.09] and - 13.49% [95% CI - 14.52, - 12.40]) after the surgery. In conclusion, BS was associated with sustained declines in FM and BFP, from 1 to 12 months, with no indication of plateau phase post-surgery post-operatively. The present study emphasizes that post-bariatric care should have more focus on FM loss during 1-year post-surgery to identify the patients at risk for fat loss plateau.

The Role of Early and Later Response on Overall Outcomes in School-Based Obesity Intervention

OBJECTIVE

Early response to obesity intervention consistently predicts long-term BMI reductions. However, little is known about how changes in weight at other times in an intervention may impact long-term outcomes. This study examined the relationship between weight-related changes that occurred early and later during an intervention and the association between these changes with overall outcomes.

METHODS

A secondary analysis of a school-based obesity intervention with replicated efficacy among Hispanic middle school students was conducted (n = 174). Linear regression models were developed in which first and second semester changes in BMI represented as a percentage of the 95th BMI percentile (%BMIp95) were separately used to predict overall %BMIp95 outcomes. First semester changes in %BMIp95 were used to predict subsequent %BMIp95 change (i.e., second semester).

RESULTS

Changes in %BMIp95 during both the first and second semesters were independently associated with overall changes from baseline (e.g., at 24 months: first semester, β = 0.59, P < 0.01; second semester, β = 1.02, P < 0.001). First semester %BMIp95 change was not associated with second semester change (β = -0.07, P = 0.32).

CONCLUSIONS

Change at any point during the intervention was predictive of overall weight outcomes. Additional research is needed to understand patterns of weight changes throughout interventions to better understand long-term outcomes.

Relationships Among Dietary Cognitive Restraint, Food Preferences, and Reaction Times

Objective

To assess the associations between dietary cognitive restraint, disinhibited eating, and how taste and health perceptions relate to food preference; and further, whether cognitive restraint and disinhibited eating are associated with food preference decision reaction time.

Methods

Five hundred and seventeen adults participated in the study. Dietary cognitive restraint and disinhibited eating were assessed using the shortened Three-Factor Eating Questionnaire (TFEQ-R18). Participants also completed a dietary decision-making task to examine their food-related decisions. Participants were presented with 50 food items and asked to rate them for health and for taste. Participants were then presented with a reference food item and comparison items one at a time and asked to indicate which of the two foods they would prefer to eat.

Results

Participants with higher levels of cognitive restraint were more sensitive to health perceptions whereas those with higher levels of disinhibited eating were more sensitive to taste perceptions when indicating food preference. Reaction time analysis corroborated these results. Being classified as high for cognitive restraint was associated with faster reaction times if the preferred food was rated as healthier than the referent food. Conversely, being classified as high for disinhibited eating was associated with faster reaction times if the preferred food was rated as tastier than the referent food.

Conclusion

The dietary decision-making task appears to capture distinct aspects of dietary restraint and disinhibition and may be useful in future studies to measure and/or alter levels of dietary restraint and disinhibition.

Control-theory models of body-weight regulation and body-weight-regulatory appetite

Human body weight (BW), or some variable related to it, is physiologically regulated. That is, negative feedback from changes in BW elicits compensatory influences on appetite, which may be called BW-regulatory appetite, and a component of energy expenditure (EE) called adaptive thermogenesis (AdEE). BW-regulatory appetite is of general significance because it appears to be related to a variety of aspects of human appetite beyond just energy intake. BW regulation, BW-regulatory appetite and AdEE are frequently discussed using concepts derived from control theory, which is the mathematical description of dynamic systems involving negative feedback. The aim of this review is to critically assess these discussions. Two general types of negative-feedback control have been invoked to describe BW regulation, set-point control and simple negative-feedback control, often called settling-point control in the BW literature. The distinguishing feature of set-point systems is the existence of an externally controlled target level of regulation, the set point. The performance of almost any negative-feedback regulatory system, however, can be modeled on the basis of feedback gain without including a set point. In both set-point and simple negative-feedback models of BW regulation, the precision of regulation is usually determined mainly by feedback gain, which refers to the transformations of feedback into compensatory changes in BW-regulatory appetite and AdEE. Stable BW most probably represents equilibria shaped by feedback gain and tonic open-loop challenges, especially obesogenic environments. Data indicate that simple negative-feedback control accurately models human BW regulation and that the set-point concept is superfluous unless its neuroendocrine representation is found in the brain. Additional research aimed at testing control-theory models in humans and non-human animals is warranted.

Brain structures associated with eating behaviors in normal-weight young females

Eating behaviors play an important role in individuals' development, and restrained eaters have a higher risk of obesity in the future. In the present study, we used the Three-Factor Eating Questionnaire to measure restrained eating, uncontrolled eating, and emotional eating in 158 young, normal-weight, Chinese women. We developed a multiple linear regression model to identify significant structural brain changes associated with the above-mentioned eating behaviors. Uncontrolled eating scores were positively associated with the gray matter volume (GMV) of the cerebellum, and negatively associated with the GMV on the left side of the anterior cingulate cortex, middle cingulate cortex, and supplementary motor areas, indicating that uncontrolled eating behaviors not only are less inhibitory but also appear to be associated with the low-level processing of appetite. Increased GMV on the right side of the precuneus was associated with a higher level of restrained eating, which might be thus related to a lower sensitivity to behavioral inhibition in young females who follow a diet. In addition, we did not find a relationship between emotional eating behavior and GMV. Our findings show that eating-behavior-related structural brain changes may lead to a decrease in inhibition and an increase in food sensitivity.

Effect of Energy Restriction on Eating Behavior Traits and Psychobehavioral Factors in the Low Satiety Phenotype

Studies have shown that individuals with low satiety efficiency may be more susceptible to weight gain, but little is known about the effect of weight loss intervention outcomes in these individuals. This study aimed to evaluate the impact of an energy-restricted weight loss intervention on eating behavior traits and psychobehavioral factors in individuals differing in their satiety responsiveness. A pooled cohort of individuals who were overweight or obese (n = 100; aged 39 ± 9 years) participating in a 12- to 15-week weight loss program targeting an energy deficit of 500–700 kcal/day were included in this study. Satiety responsiveness was determined by a median split of the mean satiety quotient based on appetite sensations measured in response to a test meal at baseline (low satiety responsiveness (LSR) vs. high satiety responsiveness (HSR)). Anthropometric variables, eating behavior traits, psychobehavioral factors, and ad libitum energy intake were assessed before and after the intervention. Although similar weight loss was observed between the LSR and HSR groups (−3.5 ± 3.2 vs. −3.8 ± 2.8 kg, p = 0.64) in response to an energy-restricted weight loss intervention, changes in eating behavior traits were different between groups. Individuals with LSR had a higher increase in cognitive restraint (+5.5 ± 4.1 vs. +3.5 ± 3.5, p = 0.02) and some of its subscales and a lower decrease in situational susceptibility to disinhibition (−0.6 ± 1.1 vs. −1.2 ± 1.3, p = 0.02) in response to the intervention compared to the HSR group. In conclusion, energy-restricted weight loss intervention seems to trigger undesirable changes in some eating behavior traits in individuals more vulnerable to overeating, which could increase their susceptibility to weight regain.

Food Intake and Eating Behavior After Bariatric Surgery

Obesity is an escalating global chronic disease. Bariatric surgery is a very efficacious treatment for obesity and its comorbidities. Alterations to gastrointestinal anatomy during bariatric surgery result in neurological and physiological changes affecting hypothalamic signaling, gut hormones, bile acids, and gut microbiota, which coalesce to exert a profound influence on eating behavior. A thorough understanding of the mechanisms underlying eating behavior is essential in the management of patients after bariatric surgery. Studies investigating candidate mechanisms have expanded dramatically in the last decade. Herein we review the proposed mechanisms governing changes in eating behavior, food intake, and body weight after bariatric surgery. Additive or synergistic effects of both conditioned and unconditioned factors likely account for the complete picture of changes in eating behavior. Considered application of strategies designed to support the underlying principles governing changes in eating behavior holds promise as a means of optimizing responses to surgery and long-term outcomes.

Eating-Related and Psychological Outcomes of Health at Every Size Intervention in Health and Social Services Centers Across the Province of Québec

Purpose:

To report the outcomes of a Health at Every Size (HAES) intervention in a real-world setting.

Design:

Quasi-experimental design evaluating eating behaviors and psychological factors.

Setting:

The HAES intervention is offered in Health and Social Services Centers in Québec (Canada).

Participants:

For this study, 216 women (body mass index [BMI]: 35.76 [6.80] kg/m2) who participated to the HAES intervention were compared to 110 women (BMI: 34.56 [7.30] kg/m2) from a comparison group.

Intervention:

The HAES intervention is composed of 14 weekly meetings provided by health professionals. It focuses on healthy lifestyle, self-acceptance, and intuitive eating.

Measures:

Eating behaviors (ie, flexible restraint, rigid restraint, disinhibition, susceptibility to hunger, intuitive eating, and obsessive-compulsive eating) and psychological correlates (ie, body esteem, self-esteem, and depression) were assessed using validated questionnaires at baseline, postintervention, and 1-year follow-up.

Analysis:

Group, time, and interaction effects analyzed with mixed models.

Results:

Significant group by time interactions were found for flexible restraint ( P = .0400), disinhibition ( P < .0001), susceptibility to hunger ( P < .0001), intuitive eating ( P < .0001), obsessive–compulsive eating ( P < .0001), body-esteem ( P < .0001), depression ( P = .0057), and self-esteem ( P < .0001), where women in the HAES group showed greater improvements than women in the comparison group at short and/or long term.

Conclusion:

The evaluation of this HAES intervention in a real-life context showed its effectiveness in improving eating-, weight-, and psychological-related variables among women struggling with weight and body image.

Attenuating the Biologic Drive for Weight Regain Following Weight Loss: Must What Goes Down Always Go Back Up?

Metabolic adaptations occur with weight loss that result in increased hunger with discordant simultaneous reductions in energy requirements—producing the so-called energy gap in which more energy is desired than is required. The increased hunger is associated with elevation of the orexigenic hormone ghrelin and decrements in anorexigenic hormones. The lower total daily energy expenditure with diet-induced weight loss results from (1) a disproportionately greater decrease in circulating leptin and resting metabolic rate (RMR) than would be predicted based on the decline in body mass, (2) decreased thermic effect of food (TEF), and (3) increased energy efficiency at work intensities characteristic of activities of daily living. These metabolic adaptations can readily promote weight regain. While more experimental research is needed to identify effective strategies to narrow the energy gap and attenuate weight regain, some factors contributing to long-term weight loss maintenance have been identified. Less hunger and greater satiation have been associated with higher intakes of protein and dietary fiber, and lower glycemic load diets. High levels of physical activity are characteristic of most successful weight maintainers. A high energy flux state characterized by high daily energy expenditure and matching energy intake may attenuate the declines in RMR and TEF, and may also result in more accurate regulation of energy intake to match daily energy expenditure.

Effects of the Mediterranean Diet before and after Weight Loss on Eating Behavioral Traits in Men with Metabolic Syndrome

The objective of this study was to investigate the impact of the Mediterranean diet (MedDiet) consumed before and after weight loss on eating behavioral traits as measured by the Three-Factor Eating Questionnaire (TFEQ) in men with metabolic syndrome (MetS). In this fixed sequence study, 19 men with MetS (National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATPIII) criteria), aged between 24 and 62 years, first consumed a five-week standardized North American control diet followed by a five-week MedDiet, both under weight-maintaining controlled-feeding conditions. This was followed by a 20-week caloric restriction weight loss period in free-living conditions, without specific recommendations towards adhering to the principles of the MedDiet. Participants were finally subjected to a final five-week MedDiet phase under isoenergetic controlled-feeding conditions. The MedDiet before weight loss had no impact on eating behavioral traits. Body weight reduction by caloric restriction (−10.2% of initial weight) was associated with increased cognitive restraint (p < 0.0001) and with reduced disinhibition (p = 0.02) and susceptibility to hunger (p = 0.01). Feeding the MedDiet for five weeks under isoenergetic conditions after the weight loss phase had no further impact on eating behavioral traits. Results of this controlled-feeding study suggest that consumption of the MedDiet per se has no effect on eating behavioral traits as measured by TFEQ, unless it is combined with significant weight loss.

Effects of a Diet-Based Weight-Reducing Program with Probiotic Supplementation on Satiety Efficiency, Eating Behaviour Traits, and Psychosocial Behaviours in Obese Individuals

This study evaluated the impact of probiotic supplementation (Lactobacillus rhamnosus CGMCC1.3724 (LPR)) on appetite sensations and eating behaviors in the context of a weight-reducing program. Obese men (n = 45) and women (n = 60) participated in a double-blind, randomized, placebo-controlled trial that included a 12-week weight loss period (Phase 1) based on moderate energy restriction, followed by 12 weeks of weight maintenance (Phase 2). During the two phases of the program, each subject consumed two capsules per day of either a placebo or a LPR formulation (10 mg of LPR equivalent to 1.6 108 CFU/capsule, 210 mg of oligofructose, and 90 mg of inulin). The LPR supplementation increased weight loss in women that was associated with a greater increase in the fasting desire to eat (p = 0.03). On the other hand, satiety efficiency (satiety quotient for desire to eat) at lunch increased (p = 0.02), whereas disinhibition (p = 0.05) and hunger (p = 0.02) scores decreased more in the LPR-treated women, when compared with the female control group. Additionally, the LPR female group displayed a more pronounced decrease in food craving (p = 0.05), and a decrease in the Beck Depression Inventory score (p = 0.05) that was significantly different from the change noted in the placebo group (p = 0.02), as well as a higher score in the Body Esteem Scale questionnaire (p = 0.06). In men, significant benefits of LPR on fasting fullness and cognitive restraint were also observed. Taken together, these observations lend support to the hypothesis that the gut-brain axis may impact appetite control and related behaviors in obesity management.

Genetic Testing for Obesity: Implications and Challenges

PURPOSE OF REVIEW

This review summarizes the experimental literature on behavioral outcomes and psychological effects of genetic testing for obesity. Such tests, although of dubious value, are increasingly marketed to the public, and there has been concern that while results may encourage some consumers to increase the healthfulness of their lifestyles, others may interpret feedback in maladaptive ways.

RECENT FINDINGS

Hypothetical vignettes have been used in artificial settings; few studies have investigated outcomes of actual test results. At present, the effects of genetic testing for obesity seem limited to improving consumers' weight control intentions and motivation rather than actual dietary behavior. Evidence for negative psychological consequences is scarce and seems of greater concern for normal weight persons than for those who are overweight. Better research designs carried out in the field rather than the laboratory with more diverse samples are needed.

Neuroendocrine adaptations to bariatric surgery

The global epidemic of obesity and its related disease in combination with robust physiological defence of intentional weight loss generates a pressing need for effective weight loss therapies. Bariatric surgery, which works very effectively at delivering substantial sustained weight loss, has been an enigma with respect to mechanism of action. Naive concepts of restriction and malabsorption do not explain the efficacy of the most commonly used bariatric procedures. This century has seen increased interest in unravelling the mystery of the mechanisms underlying surgery associated weight loss with a focus on integrative gastrointestinal (GI) physiology, gut-brain signalling, and beyond weight loss effects on metabolism. GI interventions, some very minor, can alter GI wall stretch and pressure receptors; a range of GI hormones affecting hunger and satiety; bile acid metabolism and signalling; the characteristics of GI microbiome; portal vein nutrient sensing; and circulating concentrations of amino acids. Understanding the mechanisms involved should present targets for less invasive effective therapies.

The long-term effect of energy restricted diets for treating obesity

OBJECTIVE

To quantify the effectiveness of diet interventions by systematic review of the long-term effects of energy restricted diets in individuals with overweight and obesity.

METHODS

A systematic literature search was conducted for all clinical trials studying the effect of energy restricted diets on body weight in individuals with a BMI>25 kg/m(2) with a follow-up of at least 3 years and a minimum of 50 participants. Weight change from baseline and rates of loss to follow-up at the longest follow-up were extracted and analyzed using random-effects models.

RESULTS

Weighted mean weight loss after 3 years follow-up was 3.5% (95% CI 0.2-6.8%) (n = 6,163) and after 4 years follow-up 4.5% (95% CI 4.3-4.8%) (n = 5,696). Energy restricted diets (n = 1,433) resulted in an average 2.9% (95% CI -3.8 to -2.1%) greater weight loss compared to untreated control groups (n = 1,361). Weight regain was observed in the majority of individuals in all studies. Interpretation of the data is limited by high rates of loss to follow-up and lack of truly untreated control groups.

CONCLUSIONS

On average, the long-term effect of diets on body weight in individuals with obesity is modest, and the response is highly heterogeneous.

The longitudinal association between inflammation and incident depressive symptoms in men: the effects of hs-CRP are independent of abdominal obesity and metabolic disturbances

BACKGROUND

This cohort study evaluates whether the association between low-grade inflammation and incident depressive symptoms is independent of abdominal obesity and metabolic disturbances.

METHODS

A cohort of 1167 non-depressed men aged 35 to 80 years were followed up over 5 years to assess incident depressive symptoms measured by the Centre for Epidemiology Scale-Depression or Beck Depression Inventory-I. Venous tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and high sensitivity C-reactive protein (hsCRP) were quantified at baseline and 5years. Logistic regression determined whether hsCRP, IL-6 and TNF-α were associated with incident depressive symptoms independent of abdominal obesity and metabolic factors. Ancillary analysis utilizing depression z scores stratified participants by waist circumference ≥ 102 cm and ≥2 metabolic disturbances.

RESULTS

Incident depressive symptoms occurred in 95 men at 5 years (8.14% of total). Clinically relevant depressive symptoms were associated with baseline hsCRP (adjusted OR=1.04; 95% CI 1.00-1.07, p=.03) and annualized ΔhsCRP (adjusted OR=1.04; 95% CI 1.01-1.08, p=.02). Ancillary analysis showed that the association between annualized ΔhsCRP and depression z score was only significant in men with waist circumference<102 cm (β=.19, p<.001) and ≤1 metabolic disturbance (β=.18, p<.001). None of the measured cytokines were significantly associated with depression.

CONCLUSIONS

hsCRP and annualized ΔhsCRP were positively associated with depressive symptoms in a cohort of men. Further investigation into the role of abdominal obesity and metabolic disturbances in the inflammation-depression hypothesis is warranted.

Zinc-α2-glycoprotein expression in adipose tissue of obese postmenopausal women before and after weight loss and exercise + weight loss

OBJECTIVE

Zinc-Alpha 2-Glycoprotein (ZAG) has recently been implicated in the regulation of adipose tissue metabolism due to its negative association with obesity and insulin resistance. The purpose of this study is to investigate the relationships between adipose tissue ZAG expression and central obesity, and the effects of six-months of weight loss (WL) or aerobic exercise + weight loss (AEX + WL) on ZAG expression.

DESIGN AND METHODS

A six-month, longitudinal study of 33 healthy, overweight or obese postmenopausal women (BMI: 25-46 kg/m(2)) was conducted. Abdominal and gluteal adipose tissue samples were obtained before and after AEX + WL (n = 17) and WL (n = 16). ZAG expression was determined by RT-PCR.

RESULTS

Prior to interventions, abdominal ZAG expression was negatively correlated with visceral fat (r = -0.50, P < 0.005), sagittal diameter (r = -0.42, P < 0.05), and positively related to VO(2)max (r = 0.37, P < 0.05). Gluteal ZAG expression was negatively correlated with weight, fat-free mass, visceral fat, resting metabolic rate, and fasting insulin (r = -0.39 to -0.50, all P < 0.05). Abdominal ZAG mRNA levels increased, though not significantly, 5% after AEX + WL and 11% after WL. Gluteal ZAG mRNA levels also did not change significantly with AEX + WL and WL.

CONCLUSIONS

Abdominal ZAG expression may be important in central fat accumulation and fitness but only modestly increase (nonsignificantly) with weight reduction alone or with aerobic training in obese postmenopausal women.

Brain-derived neurotrophic factor, but not body weight, correlated with a reduction in depression scale scores in men with metabolic syndrome: a prospective weight-reduction study

BACKGROUND

Obesity, a critical component of metabolic syndrome (MetS), is associated with depression. Deficiency of brain-derived neurotrophic factor (BDNF) is involved in the mechanism of depression. We hypothesized that weight reduction would improve depressive symptoms via increasing BDNF levels in obese men.

METHODS

Male adults with obesity were enrolled in a weight-reduction program for twelve weeks. All subjects underwent daily caloric restriction and an exercise program which was regularly assessed in group classes. Fasting blood samples and Zung Self-Rating Depression Scale (Zung SDS) scores were collected for assessments before and after the study.

RESULTS

A total of 36 subjects completed this program. The average reduction in body weight was 8.4 ± 5.1 kg (8.8 ± 5.1%, P < 0.001). Fasting serum BDNF significantly increased after the study (from 40.4 ± 7.8 to 46.9 ± 8.9 ng/ml, P < 0.001). However, the depression symptoms, as assessed by the Zung Self-Rating Depression Scale (Zung SDS), did not reduce significantly (P = 0.486). Divided into subgroups based on changes in BDNF, Zung SDS scores were significantly reduced in subjects with greater BDNF increase than in those with minor BDNF change (-3.9 ± 6.2 vs. 2.3 ± 6.7, P = 0.009). The increased percentage of BDNF was inversely correlated with the change in Zung SDS (r = -0.380, P = 0.022). Multivariate regression analysis showed that reduction in BDNF was independently associated with change in Zung SDS (95% confidence interval -0.315 to -0.052, P = 0.008).

CONCLUSION

Zung SDS only significantly improved in men with increased fasting BDNF levels after a lifestyle intervention.

TRIAL REGISTRATION

(NCT01065753, ClinicalTrials.gov).

Acute effect on satiety, resting energy expenditure, respiratory quotient, glucagon-like peptide-1, free fatty acids, and glycerol following consumption of a combination of bioactive food ingredients in overweight subjects

OBJECTIVE

A combination of bioactive food ingredients (capsaicinoids, epigallocatechin gallate, piperin, and l-carnitine, CBFI) may promote satiety and thermogenesis. The study was conducted in order to assess whether there is any effect on satiety, resting energy expenditure (REE), respiratory quotient, glucagon-like peptide-1 (GLP-1), free fatty acids (FFA) and glycerol release, following a standardized mixed meal with or without single consumption of a CBFI.

DESIGN

An 8-week randomized double-blind placebo-controlled trial.

SETTING

Dietetic and Metabolic Unit, Azienda di Servizi alla Persona, University of Pavia and "Villa delle Querce" Clinical Rehabilitation Institute, Rome, Italy.

PARTICIPANTS

Thirty-seven overweight adults (body mass index [BMI]: 25-35).

INTERVENTION

Nineteen overweight subjects were included in the supplemented group (14 women, 5 men; age 46.4 ± 6.4; BMI: 30.5 ± 3.3) and 18 in the placebo group (13 women, 5 men; age 40.8 ± 11.5; BMI: 30.1 ± 2.6). Satiety was assessed using 100-mm visual analogue scales (VAS) and the area under the curve was calculated.

RESULTS

All measured parameters increased significantly in comparison with baseline in response to meal, both with CBFI and with placebo. However, throughout the study day, the supplemented group experienced a significantly greater increase than the placebo group in their sensation of satiety following acute administration of the supplement.

CONCLUSION

CBFI may therefore be of great value in the treatment of overweight patients by increasing satiety and stimulating thermogenesis.

Biological mechanisms that promote weight regain following weight loss in obese humans

Weight loss dieting remains the treatment of choice for the vast majority of obese individuals, despite the limited long-term success of behavioral weight loss interventions. The reasons for the near universal unsustainability of behavioral weight loss in [formerly] obese individuals have not been fully elucidated, relegating researchers to making educated guesses about how to improve obesity treatment, as opposed to developing interventions targeting the causes of weight regain. This article discusses research on several factors that may contribute to weight regain following weight loss achieved through behavioral interventions, including adipose cellularity, endocrine function, energy metabolism, neural responsivity, and addiction-like neural mechanisms. All of these mechanisms are engaged prior to weight loss, suggesting that these so called "anti-starvation" mechanisms are activated via reductions in energy intake, rather than depletion of energy stores. Evidence suggests that these mechanisms are not necessarily part of a homeostatic feedback system designed to regulate body weight, or even anti-starvation mechanisms per se. Although they may have evolved to prevent starvation, they appear to be more accurately described as anti-weight loss mechanisms, engaged with caloric restriction irrespective of the adequacy of energy stores. It is hypothesized that these factors may combine to create a biological disposition that fosters the maintenance of an elevated body weight and works to restore the highest sustained body weight, thus precluding the long-term success of behavioral weight loss. It may be necessary to develop interventions that attenuate these biological mechanisms in order to achieve long-term weight reduction in obese individuals.

Potential mechanisms by which bariatric surgery improves systemic metabolism

Over the past several decades, excessive body weight has become a major health concern. As the obesity epidemic continues to expand, metabolic disorders associated with excess body weight, including type 2 diabetes, dyslipidemia, hypertension, and cardiovascular disease, have exponentially increased. Dysregulation of satiety hormones and factors that regulate long-term energy storage can disrupt normal metabolic functions and lead to excess body fat. While diet and exercise seem to provide a logical means for weight loss, an unhealthy lifestyle coupled to responses initiated by perceived energy deficit impede sustained long term weight loss. Furthermore, because of the additional lack of effective pharmaceutical interventions to treat excess body weight, patients with severe obesity resort to bariatric surgery as an effective alternative for treatment of obesity and resolution of its associated comorbidities. Interestingly, the precise method by which bariatric surgery promotes rapid improvement in systemic metabolism and long-term weight loss remains incompletely understood and may vary between procedures. Multiple mechanisms likely contribute to the improved glucose metabolism seen after bariatric surgery, including caloric restriction, changes in the enteroinsular axis, alterations in the adipoinsular axis, release of nutrient-stimulated hormones from endocrine organs, stimulation from the nervous system, and psychosocial aspects including a dramatic improvement in quality of life. The current review will highlight the potential contribution of these responses to the improvement in systemic energy metabolism elicited by bariatric surgery.

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.

Leptin reverses declines in satiation in weight-reduced obese humans

BACKGROUND

Individuals who are weight-reduced or leptin deficient have a lower energy expenditure coupled with higher hunger and disinhibition and/or delayed satiation compared with never-weight-reduced control subjects. Because exogenous leptin inhibits feeding in congenitally leptin-deficient humans, reduced leptin signaling may reduce the expression of feeding inhibition in humans.

OBJECTIVE

The objective was to test the hypothesis that reduced leptin signaling may reduce the expression of feeding inhibition (ie, blunt satiation) in humans by examining the effects of leptin repletion on feeding behavior after weight loss.

DESIGN

Ten obese humans (4 men, 6 women) were studied as inpatients while they received a weight-maintaining liquid-formula diet. Satiation was studied by measuring intake and ratings of appetite-related dispositions 3 h after ingestion of 300 kcal of the liquid-formula diet. The subjects were studied at each of 3 time periods: 1) while they maintained their usual weight (Wt(initial)) and then after weight reduction and stabilization at 10% below initial weight and while they received 5 wk of either 2) twice-daily injections of placebo (Wt(-10%placebo)) or 3) "replacement doses" of leptin (Wt(-10%leptin)) in a single-blind crossover design with a 2-wk washout period between treatments. Energy expenditure was also measured at each study period.

RESULTS

Both energy expenditure and visual analog scale ratings that reflect satiation were significantly lower at Wt(-10%placebo) than at Wt(initial) and Wt(-10%leptin).

CONCLUSION

The results are consistent with the hypothesis that the absence of leptin signaling after weight loss may blunt the expression of feeding inhibition in humans.

Biology's response to dieting: the impetus for weight regain

Dieting is the most common approach to losing weight for the majority of obese and overweight individuals. Restricting intake leads to weight loss in the short term, but, by itself, dieting has a relatively poor success rate for long-term weight reduction. Most obese people eventually regain the weight they have worked so hard to lose. Weight regain has emerged as one of the most significant obstacles for obesity therapeutics, undoubtedly perpetuating the epidemic of excess weight that now affects more than 60% of U.S. adults. In this review, we summarize the evidence of biology's role in the problem of weight regain. Biology's impact is first placed in context with other pressures known to affect body weight. Then, the biological adaptations to an energy-restricted, low-fat diet that are known to occur in the overweight and obese are reviewed, and an integrative picture of energy homeostasis after long-term weight reduction and during weight regain is presented. Finally, a novel model is proposed to explain the persistence of the "energy depletion" signal during the dynamic metabolic state of weight regain, when traditional adiposity signals no longer reflect stored energy in the periphery. The preponderance of evidence would suggest that the biological response to weight loss involves comprehensive, persistent, and redundant adaptations in energy homeostasis and that these adaptations underlie the high recidivism rate in obesity therapeutics. To be successful in the long term, our strategies for preventing weight regain may need to be just as comprehensive, persistent, and redundant, as the biological adaptations they are attempting to counter.

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.

Relative changes in resting energy expenditure during weight loss: a systematic review

A more comprehensive understanding of the effects of weight loss on the changes in resting energy expenditure (EE) is relevant. A MEDLINE search was performed to identify studies with information relevant to this systematic review. From this search, the mean rate of resting EE decrease relative to weight loss was calculated from 90 available publications. A decrease of resting EE relative to weight loss of -15.4 +/- 8.7 kcal kg(-1) was observed from 2977 [corrected] subjects. No sex differences were noted in the overall resting EE decrease relative to weight loss. However, a significant sex differences was seen with pharmacological interventions, which seemed to depress the resting EE relative to weight loss to a greater extent in men than in women (P < 0.05). A greater drop in resting EE relative to weight loss was observed for short interventions (more than 2 but less than 6 weeks) when compared with long interventions (<6 weeks) (-27.7 +/- 6.7 vs. -12.8 +/- 7.1 kcal kg(-1)) (P < 0.001). Men and women have a similar decrease in resting EE relative to weight loss except in the case of pharmacological interventions. Short interventions also produced greater resting EE losses relative to weight loss.

Psychological Impact of a "Health-at-Every-Size" Intervention on Weight-Preoccupied Overweight/Obese Women

The aim of the present study was to assess the impact of a "Health-at-every-size" (HAES) intervention on psychological variables and body weight the weight-preoccupied overweight/obese women. Those women were randomized into three groups (1) HAES, (2) social support (SS), (3) waiting-list (WL), and were tested at baseline, post-treatment and six-month and one-year follow-ups. All participants presented significant psychological improvement no matter if they received the HAES intervention or not. However, even if during the intervention, the three groups showed improvements, during the follow up, the HAES group continued to improve while the other groups did not, even sometimes experiencing some deterioration. Furthermore, in the HAES group only, participant's weight maintenance 12 months after the intervention was related to their psychological improvement (quality of life, body dissatisfaction, and binge eating) during the intervention. Thus, even if, in the short-term, our study did not show distinctive effects of the HAES intervention compared to SS and WL on all variables, in the long-term, HAES group seemed to present a different trajectory as psychological variables and body weight are maintained or continue to improve, which was not the case in other groups. These differential long-term effects still need to be documented and further empirically demonstrated.

Energy intake in weight-reduced humans

Almost anyone who has ever lost weight can attest that it is harder to sustain weight loss than to lose weight. Maintenance of a 10% or greater reduced body weight is accompanied by decreases in energy expenditure to levels significantly below what is predicted solely on the basis of weight and body composition changes. This disproportionate decline in energy expenditure would not be sufficient to account for the over 80% recidivism rate to pre-weight loss levels of body fatness after otherwise successful weight reduction if there were a corresponding reduction in energy intake. In fact, reduced body weight maintenance is accompanied by increased energy intake above that required to maintain reduced weight. The failure to reduce energy intake in response to decreased energy output reflects decreased satiation and perception of how much food is eaten and multiple changes in neuronal signaling in response to food which conspire with the decline in energy output to keep body energy stores (fat) above a CNS-defined minimum (threshold). Much of this biological opposition to sustained weight loss is mediated by the adipocyte-derived hormone "leptin."

The effect of eating behavior on weight loss and maintenance during a lifestyle intervention

OBJECTIVE

To investigate the effects of intensive counseling on eating behavior and weight loss and maintenance and their associations.

METHODS

A randomized weight loss counseling intervention with follow-up of 18 months, conducted between 2002-2004 at Oulu University Hospital, Finland included obese adults (n=82, body mass index >27 kg/m(2)). Subjects were randomized into 1) intensive counseling and 2) short-term counseling. Forty-nine subjects who completed the study were included. Eating behavior was repeatedly assessed by the Three Factor Eating Questionnaire-18 and Binge Eating Scale.

RESULTS

Eating behavior improved in both groups. Effect of counseling was -5.0+/-5.7 kg compared with -2.4+/-2.5 kg in the control group (p<0.05 between the groups) during the first 6 months. At 18 months the weight loss results were -2.6+/-6 kg and -0.7+/-3.5 kg, respectively (NS). Success in weight loss maintenance is associated with improved eating behavior (p<0.05). By contrast, failure in weight loss is associated with high scores of uncontrolled eating and binge eating symptoms at the baseline (p<0.05).

CONCLUSIONS

Both intensive and short-term interventions improved eating behavior and weight loss but there was no difference between the two modes of intervention. The association between the improvement of eating behaviour and the success of weight loss suggests a causal relationship which however should be confirmed in a prospective study focusing specifically on this aspect.

Influence of changes in body composition and adaptive thermogenesis on the difference between measured and predicted weight loss in obese women

BACKGROUND

There is a difference between measured and predicted weight loss in obese patients. This might be explained by the composition of weight loss, adaptive thermogenesis, or poor compliance.

PATIENTS AND METHODS

48 overweight and obese female patients (31.5 +/- 6.1 years; BMI 35.4 +/- 4.4 kg/m(2)) were investigated before and 13.9 +/- 2.4 weeks after dietary treatment (1,000 kcal/day). Body composition was measured by air-displacement plethysmography and resting energy expenditure (REE) by indirect calorimetry. Physical activity was assessed using electronic pedometers in order to calculate total energy expenditure from REE and physical activity level (PAL). Fat mass (FM) and fat-free mass (FFM) were converted into caloric equivalents using 9.45 kcal/g FM and 1.13 kcal/g FFM. Predicted weight loss was calculated by Wishnofsky's '7,700 kcal/kg rule'.

RESULTS

Weight (-8.4 +/- 3.9 kg; p < 0.001), FM (-7.8 +/- 3.6 kg; p < 0.001), and FFM (-0.6 +/- 2.0 kg; p < 0.05) decreased with caloric restriction. Measured weight loss was only 44% of the predicted value. Since FM contributed to 87% of weight loss, the energy deficit/kg weight loss was considerably higher (9,098 +/- 2,349 kcal/kg) than the assumed 7,700 kcal/kg. Adaptive thermogenesis after weight loss was significant in 26 of 48 women (-3.2 +/- 1.2 kcal per kg FFM; p < 0.001).

CONCLUSION

14% of the difference between measured and predicted weight loss was explained by the higher proportion of FM in weight loss and 38% by adaptive thermogenesis (in 54% of the women). Thus, poor compliance was responsible for about 50% of the difference between measured and predicted weight loss only.

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.

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.