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The influence of calcium and dairy food intake on energy balance is the object of a growing scientific literature. This manuscript presents the information discussed by subject experts during a symposium on calcium and obesity, initially planned to document in a comprehensive manner the role of calcium and dairy food on energy balance and body composition. This manuscript is organized into 13 propositions statements which either resume the presentation of an invited speaker or integrate recent developments in calcium-related obesity research. More specifically, the effects of calcium and dairy consumption on body weight and adiposity level, appetite, weight loss intervention outcome, lipid-lipoprotein profile and the risk to develop metabolic syndrome are discussed together with the metabolic mechanisms proposed to explain these effects. Taken together, the observations presented in this manuscript suggest that calcium and dairy food intake can influence many components of energy and fat balance, indicating that inadequate calcium/dairy intake may increase the risk of positive energy balance and of other health problems.

Recent studies have suggested that respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea syndrome (OSAS), influence energy expenditure (EE). This influence on energy balance may be responsible for the weight changes that are often seen in individuals suffering from OSAS and COPD. However, even though EE has been assessed in several studies, be it in OSAS or COPD, there are still controversies regarding these potential relationships. Thus, the objective of this review is to describe some of the potential mechanisms that may affect EE in respiratory diseases and, thereby discuss whether there seems to be an explanation for the aforementioned relationship. The primary focus is on the oxygen transport system, which may be an important determinant for the relationship between both of these respiratory diseases and EE.

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.

Study Objective: To investigate the relationship between sleep duration and subsequent body weight and fat gain., Design: Six-year longitudinal study., Setting: Community setting., Participants: Two hundred seventy-six adults aged 21 to 64 years from the Quebec Family Study. More than half of the sample is drawn from families with at least 1 parent and 1 offspring with a body mass index of 32 kg/m2 or higher., Measurements and Results: Body composition measurements and self-reported sleep duration were determined. Changes in adiposity indices were compared between short- (5-6 hours), average- (7-8 hours), and long- (9-10 hours) duration sleeper groups. After adjustment for age, sex, and baseline body mass index, short-duration sleepers gained 1.98 kg (95% confidence interval: 1.16-2.82) more and long-duration sleepers gained 1.58 kg (95% CI: 1.02-2.56) more than did average-duration sleepers over 6 years. Short- and long-duration sleepers were 35% and 25% more likely to experience a 5-kg weight gain, respectively, as compared with average-duration sleepers over 6 years. The risk of developing obesity was elevated for short- and long-duration sleepers as compared with average-duration sleepers, with 27% and 21% increases in risk, respectively. These associations remained significant after inclusion of important covariates and were not affected by adjustment for energy intake and physical activity participation., Conclusions: This study provides evidence that both short and long sleeping times predict an increased risk of future body weight and fat gain in adults. Hence, these results emphasize the need to add sleep duration to the panel of determinants that contribute to weight gain and obesity.

Background: The potential long-term impact of low glycaemia on body fat accumulation has not been verified. Therefore, we examined the effects of low glucose concentrations on long-term energy balance and weight gain in humans., Methods: Two sets of analyses were realized in order to verify this objective. First, Study 1 consisted of 259 participants between 20 and 65 years of age selected from Phase 2 of the Quebec Family Study (QFS). The association between glucose concentrations at the end of an oral glucose tolerance test (OGTT) and changes in body mass was analysed prospectively (mean follow-up of 6 years). In addition, Study 2 consisted of 44 obese participants (20 men and 24 women) randomly assigned to a 15-week weight loss program in either a drug therapy group (fenfluramine) or a placebo group coupled with energy intake restriction. The focus of this study was the relationship between glycaemic control at the end of the treatment and post-treatment weight regain., Results: In Study 1, the glucose concentrations at 120 min of the OGTT were negatively correlated with weight gain over 6 years (r=-0.42, p<0.01). In Study 2, the weight loss program induced a mean reduction in body weight of 10 kg in the fenfluramine and placebo groups. In participants who returned for a follow-up visit (mean=81 weeks after the intervention), the glucose area below fasting values (GABF) at the end of the OGTT increased with weight loss (p<0.01) and was correlated with weight regain (r=0.74, p<0.01)., Conclusions: Lower glucose concentrations at the end of an OGTT are correlated with weight gain over time. Large amounts of weight loss are associated with low glycaemia at the end of an OGTT. These low glucose concentrations are strong predictors of the amount of weight regained after weight loss., (Copyright (c) 2007 John Wiley & Sons, Ltd.)

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.

Background: Clinical trials of low-fat diets characteristically produce small mean long-term weight loss but a large interindividual variation in response. This variation has been attributed to psychological and behavioral factors, although biological differences may also play a role., Objective: The objective was to determine whether physiologic differences in insulin secretion explain differences in weight gain among individuals consuming low- and high-fat diets., Design: Of 276 individuals followed in the Quebec Family Study for a mean of 6 y, we compared those in the lowest with those in the highest dietary fat tertiles. We performed oral-glucose-tolerance tests at baseline and examined the insulin concentration at 30 min (insulin-30) as a proxy measure of insulin secretion. Six-year changes in body weight and waist circumference were the primary endpoints. We determined the associations between insulin-30 and the primary endpoints by linear regression analysis, with adjustment for potentially confounding factors., Results: Mean changes in body weight and waist circumference did not differ significantly between the lowest- and highest-fat diet groups. However, these endpoints were strongly associated with insulin-30, especially among individuals consuming the lowest-fat diet. Insulin-30 at baseline was significantly associated with 6-y weight gain (r = 0.51, P < 0.0001) and change in waist circumference (r = 0.55, P < 0.0001) in the lowest diet fat, group [corrected], but not in the highest diet fat group (r = 0.18, P = 0.086 and r = 0.20, P = 0.058, respectively) [corrected] Individuals in the highest insulin-30 and lowest dietary fat group gained 1.8 kg more than did those in the highest insulin-30 and highest dietary fat group (51%; P = 0.034); they gained 4.5 kg more than did those in the lowest insulin-30 and lowest dietary fat group (6.5-fold; P = 0.0026)., Conclusion: A proxy measure of insulin secretion strongly predicts changes in body weight and waist circumference over 6 y in adults, especially among those consuming lower-fat diets, which demonstrates the existence of a novel diet-phenotype interaction.

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.

Aims/hypothesis: The aim of this study was to assess the relationship between sleep duration and type 2 diabetes or impaired glucose tolerance (IGT)., Methods: Anthropometric measurements and self-reported sleep duration were determined in a cross-sectional sample of 323 men and 417 women aged 21-64 years from the Quebec Family Study. Glucose homeostasis indicators were compared between short (5-6 h), 'normal' (7-8 h) and long (9-10 h) sleeper groups., Results: Using adults with 7-8 h of sleep as a reference, the adjusted odds ratio for type 2 diabetes/IGT was 1.58 (1.13-2.31) for those with 9-10 h of sleep and 2.09 (1.34-2.98) for those with 5-6 h of sleep, after adjustment for potential confounding variables. The short and long sleepers presented significantly higher total insulin AUC (p < 0.05), whereas total glucose AUC was not different between the three sleeper groups in both sexes. The mean glucose area below fasting glucose concentrations was significantly higher in short (p < 0.01) and long sleepers (p < 0.05) compared with 'normal' sleepers, and significantly higher in short (p < 0.05) compared with long sleepers in both sexes., Conclusions/interpretation: The present study provides evidence that short- and long-duration sleep times are associated with type 2 diabetes/IGT in adults, even after adjustment for several confounders. These results also showed that the lower glucose concentrations at the end of the OGTT were observed in short sleepers. According to the glucostatic theory of appetite control, this represents a stimulus that can trigger episodes of hunger and spontaneous food intake, which may explain at least in part the greater risk of overweight displayed by short sleepers, as shown in previous studies.

The aim of this pilot study was to document the association between food insecurity and body composition among men and women from urban Kampala (Uganda, East Africa) with an emphasis on the potential discrepancy between the sexes. A convenience sample of 60 food secure subjects (30 males and 30 females) and 60 food insecure subjects (30 males and 30 females) matched by age between sexes and categories were tested at home by trained research assistants. To categorize the subjects as food secure or food insecure, the Radimer/Cornell Hunger and Food Insecurity instrument was used. The percentage of overweight/obesity was 31.2% and 66.3% for food insecure men and women, respectively. Only food insecure women were significantly more likely to be overweight (ie, body mass index > or = 25; crude odds ratio=2.3, confidence interval: 1.2 to 3.4) or to have at-risk waist circumference (ie, waist circumference > or = 88 cm; crude odds ratio=2.3, confidence interval: 1.2 to 3.7) compared to their food-secure counterparts. However, after adjusting for potentially confounding effects of several environmental factors, the risk for food insecure women to be overweight or to have at-risk waist circumference was not significant, suggesting that the potential impact of food insecurity is partly expressed via variations of these factors.

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.

Background: Aging is associated with reductions in muscle mass and strength, so-called sarcopenia, and is generally characterized using muscle mass index (MMI = FFM (kg)/height (m)2). It is believed that adequate nutrition especially regarding protein intake, can delay this progression and enhance the quality of life of elders., Objectives: We examined whether the predominant source of protein consumed (animal or vegetal) by older women was associated with MMI., Design: Thirty-eight healthy, normal weight, sedentary women, aged between 57-75 years (mean age: 66 +/- 5 years old), and taking no medication that could influence metabolism were recruited. Body composition was measured by dual-energy X-ray absorptiometry; muscle protein content was measured by the use of creatinine excretion. Physical activity metabolism was obtained by the use of accelerometry, and indirect calorimetry. Finally, protein intake was measured with a 3-day dietary record., Results: Significant correlations were observed between MMI and body mass index, fat-free mass, muscle protein content, total protein intake, animal protein intake, fat mass, visceral fat and daily energy expenditure. However, a stepwise regression analysis showed animal protein intake to be the only independent predictor of MMI (r2=0.19; p=0.008)., Conclusions: Our results suggest that protein intake, especially from animal sources, may be associated with a better preservation of MMI. However, more research is needed to confirm our results.

Background and Aim: No study to date has documented the association between short sleep duration and the risk for obesity in older people. Therefore, the aim of this study was to examine cross-sectional associations between short sleep duration and variations in body fat indices in older women., Methods: Anthropometric and body composition measurements, resting energy expenditure, daily energy expenditure, daily energy intake, plasma lipid-lipoprotein profile, and self-reported sleep duration were determined in a sample of 90 women of 50 years and above., Results: The odds ratios for overweight/obesity were comparable in subjects reporting <7 hours and >or=7 hours of sleep per day, with or without adjustment for age, daily energy expenditure and daily energy intake. The results did not permit to observe any significant difference between the two sleeper groups for all the variables investigated. The correlations between sleep duration and adiposity indices were also non significant., Conclusions: Short sleep duration does not predict an increased risk of being overweight/obese in older women. This observation, together with our previously reported results in younger subjects, suggests that the sleep-body fat relationship progressively becomes less detectable with increasing in age.

Background: The effect of nutritional intake on sarcopenia has been mostly examined in class II sarcopenia, i.e. when muscle mass has sufficiently decreased to induce a loss in physical capacity. Although this provides important information regarding the treatment of sarcopenia, it may not help highlight mechanisms involved at the very beginning of its development., Hypothesis: We hypothesized that class I sarcopenia is associated with differences in antioxidant intakes (vitamins A, C, E and selenium) and status in healthy, older white men and women when physical activity and protein intake are taken into account., Design: Fat-free mass and total appendicular skeletal muscle mass was determined by dual-energy X-ray absorptiometry in 50 healthy, older white men (n = 16) and women (n = 34) aged 60-75 yrs. Physical activity energy expenditure (PAEE) was determined using a Caltrac accelerometer over a 3-d period. Dietary protein and antioxidant intakes were estimated from a 3-d food record and serum total antioxidant activity (TAA) was measured by a ferrylmyoglobin- ABTS assay., Results: The prevalence of class I sarcopenia was 23.5 % in women and 25.0 % in men; 12 participants were thus considered sarcopenic (4 men and 8 women) and 38 participants were considered nonsarcopenic (12 men and 26 women). Our results showed that PAEE, serum albumin concentrations, TAA, and the four antioxidants intake levels were similar between groups. On the other hand, our results showed that total protein intake was significantly higher (P < 0.01) in the non-sarcopenic group than in the sarcopenic group. Also, the number of Recommended Dietary Allowances (RDAs) reached for the antioxidant nutrients and protein intakes by the non-sarcopenic group was significantly higher (P < 0.01) than in the sarcopenic group., Conclusions: Although there were no significant differences between the sarcopenic and the non-sarcopenic group when antioxidant intakes were considered individually, we observed that the number of RDAs reached for antioxidant micronutrients and protein in healthy, older white men and women was lower in sarcopenic than nonsarcopenic individuals. Our results also suggest that a higher total dietary protein intake is associated with the preservation of muscle mass loss although both groups displayed values above actual RDAs. Obviously, prospective studies are needed to determine the minimum amount of protein in the diet needed to prevent class I sarcopenia and to examine the utility of antioxidant intake to combat the age-related loss in skeletal muscle mass.

Insulin plays a pivotal role in skeletal muscle protein metabolism and its action decreases with age. A loss of muscle mass, termed sarcopenia, also occurs with age. The age-associated decline in insulin sensitivity (IS) may negatively alter muscle protein metabolism and, therefore, be implicated in the aetiology of sarcopenia. However, no studies have yet compared the level of IS between older individuals with or without sarcopenia. Thus, in this study, we compared the IS of 20 class I sarcopenics (CIS), 8 class II sarcopeniscs (CIIS), and 16 non-sarcopenics (NS), among a group of otherwise healthy, non-obese, postmenopausal women. IS was estimated with the quantitative IS check index (QUICKI). Muscle mass index (MMI), which was used to determine sarcopenia, was calculated as follows: (appendicular muscle massx1.19)-1.01/h2, where h=height. Fat-free mass (FFM), fat mass (FM), and trunk FM (TFM) were measured by dual-energy X-ray absorptiometry. Accelerometry and indirect calorimetry were used to estimate resting (REE), daily (DEE), and physical activity (PAEE) energy expenditure. A 3 d food record was used to determine total energy, protein (animal and vegetal), and carbohydrate intakes. As expected, MMI and FFM differed significantly among groups. However, no significant differences were found among groups for IS, FM, TFM, REE, DEE, PAEE, or total energy, protein (both animal and vegetable), and carbohydrate intakes. Using QUICKI, a surrogate measure of IS, the present results suggest that the action of insulin does not play an important role in the development and maintenance of sarcopenia in healthy, non-obese, postmenopausal women.

Objective: To evaluate physical fitness and body composition of children involved in the 'Québec en Forme' (QEF) Project and to compare data obtained to the reference values of the 1981 Canada Fitness Survey (CFS)., Design: Cross-sectional study., Subjects: A total of 1140 children (591 boys and 549 girls) of first (7 years), second (8 years) and fourth (10 years) grade from primary schools in the City of Trois-Rivières (Québec) were selected to participate in this study., Measurements: Body mass index (BMI) and waist circumference (WC) were measured. The physical fitness tests included standing long jump, 1-min speed sit-ups and speed shuttle run., Results: The prevalence of overweight in children ranged between 20 and 30%, which represents a substantial increase compared to the 1981 CFS. The relationship between BMI and WC was highly significant in boys and girls (r=0.90 and 0.86, respectively, P<0.0001). The negative correlations between BMI or WC and the performance in all physical fitness tests were mostly significant in children of both genders (-0.16 < or = r < or = -0.45, at least P<0.05), and these relationships were significantly greater in older children (P<0.05). Based on the 1981 CFS, only 4.7-14.1% of QEF boys still performed in the upper quartile of the distribution (fit boys), whereas 32.1-69% performed not much higher than the lower quartile (unfit boys) for each fitness test. In girls, the relative fitness decrease observed in 2003 was more pronounced since only 1-9.9% of subjects performed in the upper quartile of the distribution compared to 42.8-81.4% who did not perform higher than the lower quartile of the 1981 reference scores of the CFS., Conclusion: This study shows that BMI and WC are negatively correlated with physical fitness and that these associations are more pronounced in older children. Furthermore, physical fitness of our cohort, especially in girls, was much lower than what was documented in the 1981 CFS in subjects of the same age. This study thus emphasizes the necessity to develop early interventions to improve physical fitness in children and to prevent the increase of childhood obesity.

Objective: Topiramate (TPM) has been reported to reduce body weight beyond a placebo in the treatment of obese participants, but the effect of this agent on components of energy balance has not yet been established in humans. Thus, the aim of this study was to study the impact of TPM on food preferences, measures of satiety, food intake, resting metabolic rate (RMR), and 24-h energy expenditure., Methods: The study design consisted of a 6-month, single-center, randomized, double-blind, parallel group, placebo-controlled trial with a 6-month open-label extension. The study included 68 sedentary men with abdominal obesity (waist circumference > or = 100 cm), of between 25 and 55 years of age, with a dyslipidemic profile and a body mass index (BMI) > or = 27 and < or = 40 kg/m(2)., Results: Treatment with TPM produced significant changes in anthropometric variables and body composition compared with placebo. However, at the end of the 1-year study, the placebo/TPM group showed similar weight loss and reduction in body fatness compared with the TPM/TPM group. For instance, at the end of the 12-month intervention, mean percentage of body weight loss from baseline was about -5% in both groups (-4 kg fat loss). Topiramate treatment reduced energy intake, be it in the context of an ad libitum buffet-type meal or under free living conditions. The 24-h daily energy expenditure (DEE) assessed by whole-body indirect calorimetry adjusted for body weight and age was not altered by TPM treatment., Conclusion: Topiramate treatment produced significantly greater weight loss than placebo and the majority of this loss was explained by a decrease in body fat stores. Most of the weight loss effect produced by TPM therapy was observed within a period of 6 months. Finally, TPM treatment had an impact on energy balance through a reduction in food intake that appears to have created an energy deficit of about 30,000-40,000 kcal compared with treatment with the placebo over 6 months.

The aim of this study was to evaluate the impact of knowledge-based work (KBW) on feeding behavior and spontaneous energy intake with the use of a repeated measures/within-subjects design. We used a two-session protocol including an ad libitum buffet preceded by either rest in a sitting position for 45 min or a cognitive task (reading a document and writing a summary of 350 words using a computer) over the same time period. In this regard, 15 healthy Laval University female students (mean age = 24.1+/-2.2 years, mean BMI = 24.0+/-4.3 kg/m2) were recruited to participate in this study. Anthropometric variables, energy expenditure, heart rate, blood pressure, food intake (dietary record), and appetite sensation markers were measured at each testing session, and two questionnaires [Three-Factor Eating Questionnaire (TFEQ) and State-Trait Anxiety Inventory (STAI)] were administered. In addition, a buffet-type meal was used to measure spontaneous energy intake and macronutrient preferences. We found that the mean energy expenditure of the two conditions was about comparable (difference of 13 kJ between the two tasks) whereas the mean ad libitum energy intake after the KBW task exceeded that measured after rest by 959 kJ (p < 0.01). Although a higher absolute energy intake was observed for the three macronutrients after the KBW task (p < 0.05), no specific preference was detected, as reflected by the comparable percent of energy from each macronutrient in the two conditions. No significant difference in appetite sensation markers was observed between the two conditions, although the subjects ate more in the buffet-type meal after the KBW task. Furthermore, the subjects did not compensate by decreasing food intake for the rest of the day, suggesting a net caloric surplus. We also observed negative correlations between cognitive dietary restraint (TFEQ) and spontaneous energy intake in both conditions. In conclusion, our results demonstrate that mental work solicited by KBW has the potential to induce a higher spontaneous energy intake. This also raises the possibility that KBW adds a new component to sedentariness that might further accentuate the positive energy balance that is more likely to occur when one is inactive.

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.

Objective: To explore cross-sectional associations between short sleep duration and variations in body fat indices and leptin levels during adulthood in a sample of men and women involved in the Québec Family Study., Research Methods and Procedures: Anthropometric measurements, plasma lipid-lipoprotein profile, plasma leptin concentrations, and total sleep duration were determined in a sample of 323 men and 417 women ages 21 to 64 years., Results: When compared with adults reporting 7 to 8 hours of sleep per day, the adjusted odds ratio for overweight/obesity was 1.38 (95% confidence interval, 0.89 to 2.10) for those with 9 to 10 hours of sleep and 1.69 (95% confidence interval, 1.15 to 2.39) for those with 5 to 6 hours of sleep, after adjustment for age, sex, and physical activity level. In each sex, we observed lower adiposity indices in the 7- to 8-hour sleeping group than in the 5- to 6-hour sleeping group. However, all of these significant differences disappeared after statistical adjustment for plasma leptin levels. Finally, the well-documented regression of plasma leptin levels over body fat mass was used to predict leptin levels of short-duration sleepers (5 and 6 hours of sleep), which were then compared with their measured values. As expected, the measured leptin values were significantly lower than predicted values., Discussion: There may be optimal sleeping hours at which body weight regulation is facilitated. Indeed, short sleep duration predicts an increased risk of being overweight/obese in adults and is related to a reduced circulating leptin level relative to what is predicted by fat mass. Because sleep duration is a potentially modifiable risk factor, these findings might have important clinical implications for the prevention and treatment of obesity.

The currently available drugs for long-term treatment of obesity are sibutramine and orlistat. They have been shown to be able to induce significant weight loss, with important co-morbidity reduction, allowing the maintenance of reduced body weight for at least 1-2 years. Cardiostimulating and gastrointestinal adverse effects are however not negligible.

The main aim of this cross-sectional study was to determine whether the increased body mass index (BMI) characterizing short-duration sleeping children is related to an increased predisposition to abdominal adiposity. A total of 422 children (211 boys and 211 girls) involved in the "Québec en Forme" Project were tested for body weight, height, waist circumference, and sleep duration. As there was no gender interaction with the other factors, a partial regression of waist circumference on hours of sleep was performed for both genders combined, adjusting for age, sex, BMI, parental obesity, parental education, total annual family income, frequency of taking breakfast, watching television, playing videogames, computer use, and frequency of practicing sports activities outside of school. Sleep duration had an independent effect on waist circumference, with the correlation between these variables remaining significant after adjustment for BMI and the several other covariates (r=- 0.17, p<0.001). In conclusion, these results suggest that short sleep duration favors abdominal adiposity in children. This finding is of particular concern since abdominal obesity is an important feature of the metabolic syndrome.

Introduction: Obesity has been described as the greatest current threat to human health. Although diet and lifestyle changes remain the cornerstones of therapy for obesity, weight losses are often small, and long-term success is disappointing., Discussion: When these lifestyle-modifying attempts fail, the use of anti-obesity drugs is warranted. Drug treatment is often indicated, but is somewhat limited by the minimal number of well-tolerated drugs that have proven to have long-term efficacy in maintaining body weight loss. The currently available drugs, sibutramine and orlistat, appear modestly effective in promoting weight loss. However, pharmacological therapy for obesity is in transition; expanding knowledge of the physiological mechanisms of body weight regulation has revealed new molecular targets, and more than 150 novel agents are under active development., Conclusions: Because weight regulation is complex, and redundant systems protect against perceived starvation, optimal treatment of obesity will likely require combinations of therapies. In addition, a better comprehension of the problem prior to its treatment would be preferable before targeting homeostatic pathways which could be irrelevant.

Objective: To assess the relationship between short sleep duration and obesity-related variables in children involved in the 'Québec en Forme' Project., Design: Cross-sectional study., Subjects: A total of 422 children (211 boys and 211 girls) aged between 5 and 10 years from primary schools in the City of Trois-Rivières (Québec) were selected to participate in this study., Measurements: Body weight, height and waist circumference were measured. The children were classified as normal, underweight, overweight or obese, according to body mass index (BMI) per age. An exhaustive questionnaire was administered by telephone to the parents of children., Results: The percentage of overweight/obesity was 20.0% in boys and 24.0% in girls. When compared to children reporting 12-13 h of sleep per day, the adjusted odds ratio for childhood overweight/obesity was 1.42 (95% confidence interval 1.09-1.98) for those with 10.5-11.5 h of sleep and 3.45 (2.61-4.67) for those with 8-10 h of sleep after adjustment for age, sex, and other risk factors. Parental obesity, low parental educational level, low total family income, long hours of TV watching, playing videogames or computer utilization, absence of breastfeeding and physical inactivity were also significantly associated with childhood overweight/obesity. In addition, we observed a significant negative association adjusted for age between sleep duration and body weight (-0.33, P<0.01), BMI (-0.12, P<0.01) and waist circumference (-0.24, P<0.01) in boys., Conclusion: An inverse association was observed between sleep duration and the risk to develop childhood overweight/obesity. Longitudinal research will be required to confirm a potential link of causality between these variables.

Hormonal replacement therapy (HRT) helps to prevent osteoporosis. The effect of short-term discontinuation of a long-term HRT on bone mineral density (BMD) in healthy post-menopausal women is unknown. Fifteen women on HRT (HRT users), 17 who never used HRT (non-users) and 8 former HRT users (past-HRT users) were recruited. BMD was measured by DXA. Our results allow to hypothesize that BMD may decline after short-term HRT discontinuation, which would increase the fracture risks. Indeed, our results show that past-HRT users are osteopenic just as non-users. However, these results should be re-examined using a prospective trial and a larger sample size.

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 increase in obesity prevalence is problematic as this condition is associated with health complications such as diabetes and cardiovascular diseases, more particularly when the excess body fat is stored in the deep abdominal region. The mainstay of therapy consists of behavior modification related to obesity such as overeating and physical inactivity. When these lifestyle modifying attempts fail, the use of anti-obesity drugs is warranted. Drug treatment is often indicated but is somewhat limited by the minimal number of well tolerated drugs that have proven to have long-term efficacy in maintaining body weight loss. The currently available drugs, sibutramine and orlistat, appear modestly effective in promoting weight loss. Ongoing studies continue to evaluate other drug treatments that may result in body weight reduction through a number of different mechanisms. Thus, the aim of this review is to present an overview of the current drugs available (particularly sibutramine and orlistat) as well as potential future candidates, and the impact of these agents on obesity and cardiovascular physiology. Furthermore, the therapeutic paradox of sibutramine in preventing obesity will be discussed as well as the beneficial impact of physical exercise on cardiac economy.