Showing papers by "Angelo Tremblay published in 2003"

How much physical activity is enough to prevent unhealthy weight gain? Outcome of the IASO 1st Stock Conference and consensus statement

Abstract: A consensus meeting was held in Bangkok, 21–23 May 2002, where experts and young scientists in the field of physical activity, energy expenditure and bodyweight regulation discussed the different aspects of physical activity in relation to the emerging problem of obesity worldwide. The following consensus statement was accepted unanimously. ‘The current physical activity guideline for adults of 30 minutes of moderate intensity activity daily, preferably all days of the week, is of importance for limiting health risks for a number of chronic diseases including coronary heart disease and diabetes. However for preventing weight gain or regain this guideline is likely to be insufficient for many individuals in the current environment. There is compelling evidence that prevention of weight regain in formerly obese individuals requires 60–90 minutes of moderate intensity activity or lesser amounts of vigorous intensity activity. Although definitive data are lacking, it seems likely that moderate intensity activity of approximately 45 to 60 minutes per day, or 1.7 PAL (Physical Activity Level) is required to prevent the transition to overweight or obesity. For children, even more activity time is recommended. A good approach for many individuals to obtain the recommended level of physical activity is to reduce sedentary behaviour by incorporating more incidental and leisure-time activity into the daily routine. Political action is imperative to effect physical and social environmental changes to enable and encourage physical activity. Settings in which these environmental changes can be implemented include the urban and transportation infrastructure, schools, and workplaces.’

Eating behaviors and indexes of body composition in men and women from the Québec family study.

Abstract: Objective: To put into relationship the dietary and anthropometric profile of men and women with their eating behaviors (cognitive dietary restraint, disinhibition, and susceptibility to hunger) and to assess whether gender and obesity status influence these associations. Research Methods and Procedures: Anthropometric measurements (including visceral adipose tissue accumulation), dietary profile (3-day food record), and eating behaviors (Three-Factor Eating Questionnaire) were determined in a sample of 244 men and 352 women. Results: Women had significantly higher cognitive dietary restraint and disinhibition scores than men (p < 0.0001). In both genders, scores for disinhibition and susceptibility to hunger, but not for cognitive dietary restraint, were higher in obese subjects than in overweight and nonobese subjects (p < 0.05). Positive correlations were observed between rigid restraint and most of the anthropometric variables studied (0.12 ≤ r ≤ 0.16). Moreover, in women, flexible restraint was negatively associated with body fat and waist circumference (r = −0.11). Cognitive dietary restraint and rigid restraint were positively related to BMI among nonobese women (0.19 ≤ r ≤ 0.20), whereas in obese men, cognitive dietary restraint and flexible restraint tended to be negatively correlated with BMI (−0.20 ≤ r ≤ −0.22; p = 0.10). Discussion: Gender could mediate associations observed between eating behaviors and anthropometric profile. It was also found that disinhibition and susceptibility to hunger are positively associated with the level of obesity. On the other hand, cognitive dietary restraint is not consistently related to body weight and adiposity, whereas rigid and flexible restraint are oppositely associated to obesity status, which suggests that it is important to differentiate the subscales of cognitive dietary restraint. Finally, counseling aimed at coping with disinhibition and susceptibility to hunger could be of benefit for the long-term treatment of obesity.

Do 6-y changes in eating behaviors predict changes in body weight? Results from the Québec Family Study.

Abstract: OBJECTIVE: This study was performed to examine changes in eating behaviors as assessed by the three-factor eating questionnaire (TFEQ) and to quantify the potential associations between these eating behaviors and body weight changes in a 6-follow-up study. DESIGN AND SUBJECTS: Prospective study performed in men and women who were tested twice (Visit 1=1989–1995 and Visit 2=6 y later) in the Quebec Family Study (QFS). RESULTS: Women were more restrained and less hungry than men. To reduce food intake, women relied more on strategic dieting behavior and avoided more fattening food. However, they had higher emotional and situational susceptibility to eat than men. Significant decreases in the disinhibition score were noted over time in women (P<0.01), which resulted from a decrease in habitual susceptibility behavior to increase food intake. In men, we observed an increase in the avoidance of fattening food (P<0.05). In both genders, we found that the 6-y change in restraint behavior was negatively correlated with body weight changes (P<0.05). In women, a high restraint behavior seems to promote weight gain, whereas in men, it is associated with the opposite trend. CONCLUSION: These results suggest that variables reflecting some eating behaviors are associated with body weight changes in a free-living context. However, these behaviors are expressed differently between men and women. These behaviors should be considered in clinical interventions for individuals seeking a better body weight control.

Greater than predicted decrease in energy expenditure during exercise after body weight loss in obese men.

Abstract: This study was performed retrospectively to investigate whether exercise energy expenditure (EE) measured during a standardized treadmill protocol (4.5 km/h at 0% grade) falls below predicted values after body weight loss in obese men. A reference equation was established to predict net exercise EE in a control sample of 83 obese individuals (27 kg/m(2)< or = body mass index <45 kg/m(2)), using age, fat mass and fat-free mass as independent variables. This equation was then used to predict net exercise EE in another group of 11 obese men before and after a 15-week drug-based weight loss programme that was coupled with energy restriction [-2929 kJ/day (-700 kcal/day)]. Body weight and body composition were determined by hydrodensitometry. Net exercise EE, insulin, leptin, 3,3',5-tri-iodothyronine and free thyroxine were measured after an overnight fast at baseline and 2-4 weeks after the end of the programme, when subjects were weight stable. Body weight was significantly reduced (-11%; P <0.01) at the end of the weight loss programme. At baseline, measured net exercise EE was similar to that predicted from the regression equation [19.6 and 19.8 kJ/min (4.69 and 4.74 kcal/min) respectively; not significant]. However, after the end of the intervention, measured net exercise EE was significantly below the predicted value [15.5 and 17.3 kJ/min (3.71 and 4.14 kcal/min) respectively; P <0.01]. The difference between the predicted and the measured fall in net exercise EE was significantly associated with changes in leptin concentration ( r =0.79, P <0.01), even after correction for changes in fat mass and insulin. These observations suggest that net exercise EE falls below predicted values after body weight loss. In addition, this greater than predicted decrease in net exercise EE was associated with changes in leptin.

Relationship between sex hormone-binding globulin levels and features of the metabolic syndrome.

Abstract: Previous studies have demonstrated that reduced plasma levels of sex hormone-binding globulin (SHBG) are related to alterations in several features of the metabolic syndrome in both men and women. We investigated whether SHBG level was a global predictor of the metabolic syndrome in a sample of 203 men, 173 premenopausal, and 46 postmenopausal women for whom we also obtained a detailed assessment of the metabolic profile, including body composition (hydrostatic weighing), abdominal adipose tissue areas (computed tomography), plasma lipid-lipoprotein levels, and glucose homeostasis (oral glucose challenge). Low SHBG levels were associated with increased total and abdominal adiposity in men as well as in pre- and postmenopausal women. Low SHBG levels were also associated with an altered metabolic profile, especially in premenopausal women. Subjects were subdivided according to the presence of 0, 1 to 2, or 3 or more features of the metabolic syndrome. Twenty-five percent of men were characterized by 3 features or more, whereas most premenopausal women (61.3%) had a healthy metabolic profile (0 features) and 6.9% were characterized by 3 or more features. Most postmenopausal women (54.3%) were characterized by 1 to 2 components of the metabolic syndrome, and 13.0% were characterized by 3 or more components. The proportion of subjects characterized by the metabolic syndrome (3 components or more) was lower in subjects with SHBG values in the upper tertile compared with the lower tertile in both men and premenopausal women (17.7% v 28.4% and 1.7% v 14.0%, respectively). Logistic regression analyses indicated that an SHBG level in the upper tertile was associated with a significant reduction in the probability of being characterized by the metabolic syndrome (odds ratios of 0.35, P = .02 for men and .11, P = .05 for premenopausal women, with the lower tertile as a reference). The logistic regression was not significant in postmenopausal women. These results suggest that plasma SHBG level may represent a significant predictor of the metabolic syndrome in men and premenopausal women.

Long-Term Adiposity Changes Are Related to a Glucocorticoid Receptor Polymorphism in Young Females

Abstract: Male and female preadolescents and adolescents who participated in phase 1 of the Quebec Family Study, and who were retested about 12 yr later, were recruited and subdivided on the basis of a genetic variant within the intron 2 of the glucocorticoid receptor (GRL IVS2-BclI). The increase in sc adiposity over the 12-yr follow-up period in the 4.5/2.3 genotype female subgroup was more than twice that observed in the 4.5/4.5 and the 2.3/2.3 genotype subgroups (P < 0.01). The statistical significance of this difference was essentially unchanged after adjusting for changes, over time, in percent dietary energy as fat, alcohol consumption, and participation in vigorous physical activity. In male subjects, the same trend was found, but it did not reach statistical significance. In conclusion, this study suggests that a significant interaction effect exists between variation in the glucocorticoid receptor gene and body fat gain in female subjects experiencing the transition between adolescence and adulthood. Furt...

Contribution of visceral adiposity to the exaggerated postprandial lipemia of men with impaired glucose tolerance.

Abstract: OBJECTIVE —Impaired glucose tolerance (IGT) has been associated with alterations in numerous coronary heart disease risk factors, including postprandial hyperlipidemia. An excess visceral adipose tissue accumulation is also predictive of IGT and of an exaggerated postprandial lipemia. The objective of the present study was therefore to compare the respective contributions of visceral adipose tissue accumulation versus IGT with the variation in postprandial lipemia. RESEARCH DESIGN AND METHODS —Potential differences in postprandial triglyceride (TG)-rich lipoprotein (TRL) levels following a standardized breakfast with a high fat content were examined among men characterized by normal glucose tolerance (NGT) or IGT. Sixty-seven men were classified according to their glucose tolerance status ( RESULTS —Men with IGT showed the highest TRL-TG concentrations ( P P P n = 11) for similar visceral adipose tissue accumulation, no significant difference was found in postprandial responses of all TRL-TG fractions between the two groups. CONCLUSIONS —These results provide evidence that visceral adipose tissue accumulation is an important factor involved in the deterioration of postprandial lipemia noted among men with IGT.

Aging per se does not influence glucose homeostasis: in vivo and in vitro evidence.

Abstract: OBJECTIVE - To assess the effect of age on glucose metabolism by examining 1) glucose metabolism in young and middle-aged subjects when total or regional adiposity is taken into account and 2) in vitro glucose transport in adipose tissue explants from young and middle-aged women paired for total and abdominal adiposity. RESEARCH DESIGN AND METHODS - Study 1: body composition, subcutaneous abdominal and visceral adipose tissue areas, and fasting and oral glucose-stimulated glucose and insulin were measured in 84 young and 81 middle-aged men and in 110 young and 91 middle-aged women. Study 2: glucose uptake in subcutaneous abdominal and visceral adipose tissue explants were measured in eight young and eight middle-aged women. RESULTS - Study 1: young and middle-aged men showed similar subcutaneous abdominal tissue area, whereas fat mass and visceral adipose tissue were greater in middle-aged than in young men (P < 0.01). Fat mass and subcutaneous and visceral adipose tissue areas were greater in middle-aged as compared with young women (P < 0.01). Fasting plasma glucose and the glucose response to an oral glucose tolerance test were significantly higher in middle-aged than in young men and women (P < 0.001). Statistical control for visceral adipose tissue area eliminated the difference seen in glucose response in men and women. Study 2: glucose transport in subcutaneous and omental adipose tissue did not differ between young and middle-aged women. CONCLUSIONS - 1) Visceral obesity, more than age per se, correlates with glucose intolerance in middle-aged subjects; 2) aging does not influence in vitro adipose tissue glucose uptake.

Impact of postprandial variation in triglyceridemia on low-density lipoprotein particle size

Abstract: The fasting atherogenic dyslipidemia of visceral obesity, which includes the presence of small, dense low-density lipoprotein (LDL) particles, is predictive of an increased risk of coronary heart disease (CHD). It has also been suggested that progression of atherosclerosis may be accelerated in the presence of postprandial hyperlipidemia independently from the fasting dyslipidemic state. Studies have shown that the best predictor of postprandial hyperlipidemia and of the small, dense LDL phenotype is fasting triglyceride (TG) concentration. In the present study, we evaluated the impact of postprandial hypertriglyceridemia on the variation in LDL particle size. Fasting (0 hour) and postprandial changes (2, 4, 6, and 8 hours) in LDL particle size were measured by nondenaturing 2% to 16% polyacrylamide gel electrophoresis in a sample of 49 men (mean age ± SD: 46.6 ± 9.2 years) who underwent a standardized breakfast with a high-fat (64% calories as fat) content. The postprandial increase in TG levels was associated with a transient reduction in LDL particle size, the most substantial reduction being observed 4 hours (−1.0 ± 2.4 A) after the oral fat load. Although there were strong correlations between TG-rich lipoprotein (TRL)-TG levels and LDL particle size in the fasting state (r = −0.71, P < .0001) as well as 4 hours after the oral fat load (r = −0.70, P < .0001), changes in TRL-TG concentrations during the postprandial state (from time 0 to 4 hours) were not associated with changes in LDL particle size during this period (r = −0.04, not significant [NS]). However, among subgroups of men matched for similar fasting TRL-TG levels (n = 12), subjects with the highest total area under the curve (AUC) of TRL-TG after the fat load were characterized by smaller LDL particle size at 6 and 8 hours compared with men with the lowest AUC TRL-TG (P < .02). Men displaying the highest postprandial AUC TRL-TG were also characterized by the greatest accumulation of visceral adipose tissue (AT) (P < .05). These results indicate that the hypertriglyceridemic (hyperTG) state induced by a high-fat meal is associated with a transient reduction in LDL peak particle diameter, which is not proportionate, however, to the level of TG achieved in the postprandial state. Furthermore, despite similar TG levels at baseline, viscerally obese men with an impaired postprandial lipemia had smaller LDL particles at the end of the oral fat load than obese men with a lower accumulation of visceral AT.

Na+-K+-ATPase α2-gene and skeletal muscle characteristics in response to long-term overfeeding

Abstract: The role of Na+-K+-ATPase α2-gene BglII polymorphism in the changes of skeletal muscle metabolic properties after a 100-day overfeeding protocol conducted with 12 pairs of monozygotic twins is repo...