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Biomedical subjects

N Alméras

Publications and source records attributed to N Alméras.

At least 19 recordsLinked to original sources
PubMed2007

Circulating endocannabinoid levels, abdominal adiposity and related cardiometabolic risk factors in obese men.

OBJECTIVE: The link between excess intra-abdominal adiposity (IAA) and metabolic complications leading to type 2 diabetes and cardiovascular disease is well recognized. Blockade of endocannabinoid action at cannabinoid CB(1) receptors was shown to reduce these complications. Here, we investigated the relationship between IAA, circulating endocannabinoid levels and markers of cardiometabolic risk in male obese subjects. DESIGN, SUBJECTS AND MEASUREMENTS: Fasting plasma levels of the endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), were measured by liquid chromatography-mass spectrometry in a study sample of 62 untreated asymptomatic men with body mass index (BMI) from 18.7 to 35.2 kg/m(2). RESULTS: Plasma 2-AG, but not AEA, levels correlated positively with BMI, waist girth, IAA measured by computed tomography, and fasting plasma triglyceride and insulin levels, and negatively with high-density lipoprotein cholesterol and adiponectin levels. Obese men with similar BMI values (> or =30 kg/m(2)) but who markedly differed in their amount of IAA (< vs > or = 130 cm(2), n=17) exhibited higher 2-AG levels in the presence of high IAA. No difference in 2-AG concentrations was observed between obese men with low levels of IAA vs nonobese controls. CONCLUSIONS: These results provide evidence for a relationship in men between a key endocannabinoid, 2-AG, and cardiometabolic risk factors, including IAA.

Adiponectin↗
PubMed2006

Relationship between severity of nocturnal desaturation and adaptive thermogenesis: preliminary data of apneic patients tested in a whole-body indirect calorimetry chamber.

The purpose of this study was to investigate the possibility of a relationship between the severity of obstructive sleep apnea syndrome (OSAS) and adaptive thermogenesis. Daily energy expenditure (DEE) and sleeping metabolic rate (SMR) were measured in apneic and a priori nonapneic subjects who were tested in a whole-body indirect calorimetry chamber for 24 h. The apneic patients were diagnosed by nocturnal home oximetry to determine the percentage of total recording time spent below 90% arterial oxygen saturation (% TRT <90% SaO(2)). Reference equations established from body weight and age in nonapneic subjects were used to predict DEE and SMR in apneic patients. The predicted values of the apneic patients were then compared to their measured values. No significant difference was found between predicted and measured values in SMR nor in DEE. We observed a significant relationship between the severity of nocturnal desaturation and the difference between predicted and measured DEE in apneic patients (r = -0.74, P < 0.05) and a similar negative trend with SMR (r = -0.65, P = 0.08). These preliminary data suggest that a nocturnal hypoxia may influence adaptive thermogenesis in apneic patients and complicate their body weight regulation.

Adult↗
PubMed2006

Contribution of CB1 blockade to the management of high-risk abdominal obesity.

The worldwide increase in the prevalence of type 2 diabetes represents a tremendous challenge for our healthcare system, especially if we consider that this phenomenon is largely explained by the epidemic of obesity. However, despite the well-recognized increased morbidity and mortality associated with an elevated body weight, there is now more and more evidence highlighting that abdominal adipose tissue is the fat depot that conveys the greatest risk of metabolic complications. This cluster of metabolic abnormalities has been referred to as the metabolic syndrome and this condition is largely the consequence of abdominal obesity, especially when accompanied by a high accumulation of visceral adipose tissue. This cluster of metabolic complications has also been found to be predictive of a substantially increased risk of coronary heart disease beyond the presence of traditional risk factors. Moreover, a moderate weight loss in initially abdominally obese patients is associated with a selective mobilization of visceral adipose tissue, leading to improvements in the metabolic risk profile predictive of a reduced risk of coronary heart disease and of type 2 diabetes. The recent discovery of the endocannabinoid-CB1 receptor system and of its impact on the regulation of energy metabolism represents a significant advance, which will help physicians target abdominal obesity and its related metabolic complications. In this regard, studies have shown that rimonabant therapy (the first developed CB1 blocker) could be useful for the management of clustering cardiovascular disease risk factors in high-risk abdominally obese patients through its effects not only on energy balance but also on adipose tissue metabolism. For instance, the presence of CB1 receptors in adipose tissue and the recently reported effect of rimonabant on adiponectin production by adipose cells may represent a key factor responsible for the weight loss-independent effect of this CB1 blocker on cardiometabolic risk variables.

Abdominal Fat↗
PubMed2004

Estimation of daily energy needs with the FAO/WHO/UNU 1985 procedures in adults: comparison to whole-body indirect calorimetry measurements.

OBJECTIVES: To measure daily energy expenditure (DEE) with indirect calorimetric facilities in sedentary and active subjects. To estimate daily energy needs with the FAO/WHO/UNU (1985) procedures (EDEE) and estimated energy requirement (EER) with the dietary reference intakes 2002 (DRI) in healthy adults with sedentary or high-activity conditions. To compare estimated daily energy needs with their measured values. DESIGN: Two groups of healthy subjects were tested under sedentary or high-activity conditions. In both groups, resting energy expenditure was measured after a 12-h overnight fast. DEE and basal metabolic rate (BMR) values were also measured with indirect calorimetry and compared to the relevant predicted values. Physical activity level and BMR were also estimated. SUBJECTS: A total of 45 sedentary (26 men and 19 women) and 69 active subjects (43 men and 26 women) aged 18-30 and 30-60 y. RESULTS: Measured daily energy expenditure (MDEE) was significantly lower than EDEE in sedentary men and women and in active men for the two age groups considered (P<0.05). EER was significantly lower than EDEE in both sedentary and active subjects of each subgroup (P<0.05). CONCLUSIONS: The FAO/WHO/UNU (1985) procedures may overestimate daily energy needs, particularly in sedentary individuals. However, DRI (2002) are probably more adapted to estimate real daily energy needs in sedentary and active subjects in comparison to the FAO/WHO/UNU (1985) procedures.

Adolescent↗
PubMed2002

Reduction of visceral adipose tissue during weight loss.

OBJECTIVE: The aims of the present study were to retrospectively: (1) compare how weight loss affects the reduction of adipose tissue from three different sites between men and women; and (2) to verify whether gender differences in the reduction of adipose tissue are influenced by changes in fat mass (FM) and initial levels of fat in different compartments. DESIGN: Double-blind randomized treatment with fenfluramine once daily coupled to a non-macronutrient specific energy restriction. SUBJECTS: Seventeen obese men (age 43.9+/-1.5 and body mass index (BMI) 34.3+/-0.7) and 17 obese women (age 41.2+/-1.2 and BMI 35.7+/-0.6). INTERVENTIONS: Subjects were given fenfluramine (60 mg) or placebo once daily and were also subjected to a non-macronurient specific energy restriction of -2.9 MJ/day (-700 kcal/day) for 15 weeks. RESULTS: Body weight, FM, fat-free mass (FFM), waist circumference, BMI, as well as visceral (VAT), subcutaneous abdominal (SAT) and thigh (TAT) adipose tissue were all significantly reduced. Men lost significantly more VAT (-41.6%) than SAT (-22.5%), or than TAT (-20.5%) while no site difference in fat loss was observed in women when changes were calculated as a percentage of initial levels. Men lost about twice as much fat from the VAT compartment than did women (P<0.05), even after having considered changes in FM as a potential covariate. In absolute values, TAT was reduced to a lesser extent in men than in women. However, when initial levels of respective fat depots were also taken into account, gender differences in VAT and TAT loss were no longer statistically significant. CONCLUSION: These results suggest that gender differences in VAT reduction during weight loss are independent of changes in FM. However, once initial levels of VAT are also taken into account, gender differences in the reduction of this tissue during weight loss are no longer apparent.

Adipose Tissue↗
PubMed2001

Is the relationship between adipose tissue and waist girth altered by weight loss in obese men?

OBJECTIVE: The aim of the present study was to examine whether the association of waist girth to visceral adipose tissue (AT) accumulation was altered by weight loss in abdominally obese men. RESEARCH METHODS AND PROCEDURES: We studied 45 dyslipidemic abdominally obese men (45.4 +/- 6.2 years of age; body mass index [BMI], 31.3 +/- 3.0 kg/m(2); waist circumference, 103.4 +/- 7.6 cm; total cholesterol, <6.72 mM; triglycerides, > or =1.7 mM but < or =5.65 mM; high density lipoprotein cholesterol, < or =1.2 mM). Each of them followed nutritional recommendations combined with a prescription of gemfibrozil (1200 mg/d) or a placebo for 1 year. After 6 months, a training exercise program was added at a frequency of four sessions of 60 minutes per week at 50% of maximal oxygen uptake. RESULTS: In response to the 1-year intervention program, men showed significant reductions in body weight, BMI, waist circumference, and in the partial volume of visceral and abdominal subcutaneous AT measured from two abdominal computed tomography scans performed at lumbar vertebra (L)2 to L3 and L4 to L5 levels. No change in waist-to-hip ratio was observed. Changes in visceral AT were strongly correlated with changes in body weight, BMI, and waist circumference (0.83 < r < 0.85; p < 0.001). However, a weak association was noted between waist-to-hip ratio and changes in visceral AT (r = 0.40; p < 0.05). There was no change in slopes or in intercepts before and after treatment in the relationships between volume or area of abdominal AT and anthropometric markers. DISCUSSION: Despite a greater level of the partial volume of subcutaneous AT than of the partial volume of visceral AT at baseline (p < 0.001), the greater relative reduction in the visceral AT volume in comparison with the subcutaneous AT volume suggested a preferential mobilization of visceral AT with weight loss in these abdominally obese men. The close relationship between changes in the partial volume of visceral AT and changes in cross-sectional areas of visceral AT measured at L2 to L3 (r = 0.94; p < 0.001) or L4 to L5 (r = 0.88; p < 0.001) suggests that a single computed tomography scan performed at L2 to L3 or L4 to L5 could predict changes in the partial volume of visceral AT secondary to weight loss.

Adipose Tissue↗
PubMed2001

Impact of high-intensity exercise on energy expenditure, lipid oxidation and body fatness.

OBJECTIVE: Two studies were conducted to assess the potential of an increase in exercise intensity to alter energy and lipid metabolism and body fatness under conditions mimicking real life. METHODS: Study 1 was based on the comparison of adiposity markers obtained in 352 male healthy adults who participated in the Québec Family Study who either regularly participated in high-intensity physical activities or did not. Study 2 was designed to determine the effects of high-intensity exercise on post-exercise post-prandial energy and lipid metabolism as well as the contribution of beta-adrenergic stimulation to such differences under a real-life setting. RESULTS: Results from Study 1 showed that men who regularly take part in intense physical activities display lower fat percentage and subcutaneous adiposity than men who never perform such activities, and this was true even if the latter group reported a lower energy intake (917 kJ/day, P<0.05). In Study 2, the high-intensity exercise stimulus produced a greater post-exercise post-prandial oxygen consumption as well as fat oxidation than the resting session, an effect which disappeared with the addition of propranolol. In addition, the increase in post-prandial oxygen consumption observed after the high-intensity exercise session was also significantly greater than that promoted by the low-intensity exercise session. CONCLUSION: These results suggest that high-intensity exercise favors a lesser body fat deposition which might be related to an increase in post-exercise energy metabolism that is mediated by beta-adrenergic stimulation.

Adipose Tissue↗
PubMed2001

Difference in leptin response to a high-fat meal between lean and obese men.

The aim of this study was to compare the leptin responses to a high-fat meal in lean and obese men, and to investigate whether the net leptin response (area under the incremental curve) after the meal was related to the thermic effect of food (TEF). Blood samples were collected after an overnight fast and every 2 h for 8 h after a high-fat breakfast (60 g of fat/m(2) body surface area) in 12 lean and 12 obese men for determination of glucose, insulin and leptin. The TEF was calculated as postprandial energy expenditure minus fasting energy expenditure, as measured by indirect calorimetry. Fasting plasma glucose levels were similar in lean and obese men, and increased in the same way after the meal. Fasting and postprandial plasma insulin concentrations were significantly greater in obese than in lean men (P<0.01 and P<0.05 respectively). Accordingly, obese men showed a significantly higher net insulin response than lean subjects (P<0.001). Fasting plasma leptin levels were greater in obese than in lean men (P<0.001). After the meal, plasma leptin increased significantly in lean men, whereas it decreased in obese men (group by time interaction, P<0.01). The net response of leptin was greater in lean than in obese men, but this did not reach statistical significance (P=0.07). Moreover, the TEF was similar in the two groups. No significant relationship was observed between either the net insulin response or the net leptin response after the high-fat meal and the TEF of lean subjects (-0.05 <r<0.31). In obese men, the net response of insulin was correlated significantly with TEF (r=0.70, P<0.05), whereas the net response of leptin was not (r=-0.40). These results suggest that obesity is related to an impaired regulation of leptin by insulin, since leptin levels increased in lean men but decreased in obese men following a high-fat meal. Moreover, the fact that the postprandial leptin responses of both lean and obese men were not significantly related to the TEF suggests that the ob gene product is probably not acutely involved in the control of this energy expenditure component in humans.

Adult↗
PubMed2001

Evidence for the existence of adaptive thermogenesis during weight loss.

The present study was performed to further investigate the adaptive component of thermogenesis that appears during prolonged energy restriction. Fifteen obese men and twenty obese women underwent a 15-week weight-loss programme. During this programme, body weight and composition as well as resting energy expenditure (REE) were measured at baseline, after 2 and 8 weeks of energy restriction (-2929 kJ/d) and drug therapy (or placebo), and finally 2-4 weeks after the end of the 15-week drug therapy and energy restriction intervention, when subjects were weight stable. Regression equations were established in a control population of the same age. These equations were then used to predict REE in obese men and women at baseline, after 2 and 8 weeks, as well as after the completion of the programme. In both men and women body weight and fat mass were significantly reduced in all cases) while fat-free mass remained unchanged throughout the programme. At baseline, REE predicted from the regression equation was not significantly different from the measured REE in men, while in women the measured REE was 13 % greater than predicted. After 2 weeks of energy restriction, measured REE had fallen by 469 and 635 kJ/d more than predicted and this difference reached 963 and 614 kJ/d by week 8 of treatment in men and women respectively. Once body-weight stability was recovered at the end of the programme, changes in REE remained below predicted changes in men (-622 kJ/d). However, in women changes in predicted and measured REE were no longer different at this time, even if the women were maintaining a reduced body weight. In summary, the present results confirm the existence of adaptive thermogenesis and give objective measurements of this component during weight loss in obese men and women, while they also emphasize that in women this component seems to be essentially explained by the energy restriction.

Adaptation, Physiological↗
PubMed2001

Elevated C-reactive protein: another component of the atherothrombotic profile of abdominal obesity.

Recent studies have suggested that elevated plasma C-reactive protein (CRP) levels are associated with the features of insulin resistance syndrome. In the present study, we have examined the contribution of body composition measured by hydrostatic weighing and of abdominal adipose tissue (AT) accumulation assessed by computed tomography to the variation in plasma CRP levels associated with atherogenic dyslipidemia of the insulin resistance syndrome in a sample of 159 men, aged 22 to 63 years, covering a wide range of adiposity (body mass index values from 21 to 41 kg/m(2)). Plasma CRP levels showed positive and significant correlations with body fat mass (r=0.41, P<0.0001), waist girth (r=0.37, P<0.0001), and visceral AT accumulation measured by computed tomography at L4 to L5 (r=0.28, P<0.0003). Although CRP levels were associated with plasma insulin levels measured in the fasting state and after a 75-g oral glucose load, no significant correlations were found with plasma lipoprotein levels. Finally, comparison of body fatness, of abdominal fat accumulation, and of the features of the insulin resistance syndrome across quintiles of CRP revealed major differences in body fatness and in indices of abdominal AT accumulation between the lowest and the highest CRP quintiles, whereas no significant differences were found for variables of the plasma lipoprotein-lipid profile. These results suggest that obesity and abdominal AT accumulation are the critical correlates of elevated plasma CRP levels found in men with atherogenic dyslipidemia of the insulin resistance syndrome.

Abdomen↗
PubMed2001

Deterioration of the metabolic risk profile in women. Respective contributions of impaired glucose tolerance and visceral fat accumulation.

OBJECTIVE: To determine whether the impaired glucose tolerance (IGT) state contributes to the deterioration of the metabolic profile in women after taking into account the contribution of visceral adipose tissue (AT) accumulation, as measured by computed tomography. RESEARCH DESIGN AND METHODS: We studied 203 women with normal glucose tolerance (NGT) and 46 women with IGT, defined as a glycemia between 7.8 and 11.1 mmol/l measured 2 h after a 75-g oral glucose load. RESULTS: Women with IGT were characterized by a higher visceral AT accumulation and by higher concentrations of fasting plasma glucose, insulin, and C-peptide as well as by higher plasma concentrations of cholesterol, triglycerides, and apolipoprotein B (apoB) and by greater cholesterol-to-HDL-cholesterol ratio, reduced LDL peak particle size, lower HDL-cholesterol and HDL2-cholesterol concentrations, and higher blood pressure (P < 0.01) than women with NGT. When we matched 27 pairs of women for visceral AT and fat mass as well as for menopausal status, differences previously found in LDL-cholesterol, LDL peak particle size, HDL-cholesterol, and HDL2-cholesterol concentrations as well as in the cholesterol-to-HDL-cholesterol ratio and blood pressure were eliminated, whereas triglyceride concentrations remained significantly higher in women with IGT. CONCLUSIONS: A high visceral AT accumulation is a major factor involved in the deterioration of many metabolic variables in women with IGT, with the notable exception of triglyceride concentrations, which remained significantly different between women with NGT and women with IGT after adjustment for visceral fat.

Adipose Tissue↗
PubMed2000

Hypertriglyceridemic waist: A marker of the atherogenic metabolic triad (hyperinsulinemia; hyperapolipoprotein B; small, dense LDL) in men?

BACKGROUND: The present study tested the hypothesis that simple variables, such as waist circumference and fasting plasma triglyceride (TG) concentrations, could be used as screening tools for the identification of men characterized by a metabolic triad of nontraditional risk factors (elevated insulin and apolipoprotein [apo] B and small, dense LDL particles). METHODS AND RESULTS: Results of the metabolic study (study 1) conducted on 185 healthy men indicate that a large proportion (>80%) of men with waist circumference values >/=90 cm and with elevated TG levels (>/=2.0 mmol/L) were characterized by the atherogenic metabolic triad. Validation of the model in an angiographic study (study 2) on a sample of 287 men with and without coronary artery disease (CAD) revealed that only men with both elevated waist and TG levels were at increased risk of CAD (odds ratio of 3.6, P<0.03) compared with men with low waist and TG levels. CONCLUSIONS: It is suggested that the simultaneous measurement and interpretation of waist circumference and fasting TG could be used as inexpensive screening tools to identify men characterized by the atherogenic metabolic triad (hyperinsulinemia, elevated apo B, small, dense LDL) and at high risk for CAD.

Abdomen↗
PubMed2000

Appetite after weight loss by energy restriction and a low-fat diet-exercise follow-up.

OBJECTIVE: The aim of the present study was to determine the impact of weight loss on appetite as measured by visual analog scale (VAS). METHODS: Seventeen subjects (10 men and seven women) took part in a 15 week weight loss program which consisted of drug therapy (fenfluramine 60 mg/day) or placebo coupled to an energy restriction (-2930 kJ/day; phase 1) followed by an 18 week low-fat diet-exercise follow-up (phase 2). Subjects were given a standardized breakfast before and after phase 1 as well as after phase 2. Individuals were asked to fill out VAS before and at 0, 10, 20, 30, 40, 50 and 60 min after this test meal. Blood samples were drawn before the meal and at 0, 30 and 60 min postprandially and analyzed for glucose and insulin. Fasting plasma cortisol and leptin were also determined. RESULTS: An increase in the fasting desire to eat, hunger and prospective food consumption (PFC) was observed after phase 1 and to an even greater extent after phase 2 in both men and women. In the fasting state, positive correlations were observed between changes in the desire to eat (r=0.76; P<0.05) as well as changes of PFC (r=0. 82; P<0.05) and changes in cortisol at the end of phase 1 for women. In response to phase 1, statistically significant correlations were found between changes of hunger (r=0.64; P<0.05) and desire to eat (r=0.67; P<0.05) as measured by AUC in response to the meal and changes of fasting plasma cortisol in men. The most consistent predictor of changes of baseline desire to eat (r=0.68 P<0.05), fullness (r=-0.78, P<0.05) and PFC (r=0.91, P<0.01) during phase 2 was the change in fasting cortisol in men. Changes of fullness were also associated with changes of fasting leptin in men (r=0.68; P<0. 05) during phase 2. CONCLUSION: These results suggest that weight loss is accompanied by an increase of baseline appetite in both men and women and that the most consistent predictor of these changes in appetite seems to be changes in fasting plasma cortisol.

Adult↗
PubMed2000

The association between vigorous physical activities and fat deposition in male adolescents.

PURPOSE: The aim of this study was to investigate the association between participation in vigorous physical activities (VPA) and indicators of adiposity and fat distribution in male adolescents. METHODS: Subjects were classified on the basis of the number of reported 15-min periods over 3 d during which VPA were performed. RESULTS: Body weight, fat mass, body mass index, sum of six subcutaneous skinfolds, trunk and extremity skinfolds, and trunk to extremity skinfolds ratio (T/E ratio) were all significantly and inversely related to a higher VPA participation. Moreover, T/E ratio was significantly lower in the subgroup reporting a mean of 7.8 15-min periods of activity for 3 d (equivalent to a mean of 39 min x d(-1)) compared with subjects reporting no participation. This decrease in T/E ratio was more pronounced in subjects reporting a mean of 13.6 15-min periods of VPA for 3 d. CONCLUSION: These observations reinforce the idea that excess abdominal fat accumulation can be prevented by regular participation in vigorous physical activities.

Abdomen↗
PubMed2000

Fasting insulin levels influence plasma leptin levels independently from the contribution of adiposity: evidence from both a cross-sectional and an intervention study.

The aim of the present investigation was to determine whether leptinemia is only a reflection of the status of fat stores or if insulinemia has a significant influence over leptin levels. Study 1 focused on the association between fasting plasma insulin and leptin in subjects of the Quebec Family Study who were first classified as either high- or low-insulin individuals and were then individually matched on the basis of fat mass (FM). In Study 2, 19 men and 23 women took part in a 15-week weight loss program that consisted of drug therapy (fenfluramine, 60 mg/day) or placebo coupled to an energy-restricted diet (-2930 kJ/day). Body weight, FM, and fat-free mass (assessed by underwater weighing) as well as visceral and sc abdominal and mid-thigh adipose tissue measured by computed tomography were assessed before and after weight loss. Blood samples were drawn and analyzed for fasting plasma insulin and leptin before and after weight loss. In Study 1, significant positive associations were noted between log10 transformed fasting insulin and leptin in both men (r = 0.55, P < 0.0001) and women (r = 0.48, P < 0.0001). Moreover, after having carefully matched high-insulin to low-insulin individuals on the basis of FM, significantly lower leptin levels were observed in the low-insulin groups, in men (5.5 vs. 8.1 ng/mL, P < 0.05) as well as in women (18.7 vs. 24 ng/mL, P < 0.05). Results from Study 2 showed significant reductions of body weight, FM, fat-free mass, visceral abdominal tissue, sc abdominal tissue, and mid-thigh adipose tissue levels in men and women in response to the weight loss protocol. Moreover, the decrease in fasting plasma insulin was the only significant correlate of changes in fasting plasma leptin levels during weight loss, even after corrections for changes in FM in both men (r = 0.50, P < 0.05) and women (r = 0.46, P < 0.05). These results suggest that in a population characterized by a wide range of adiposity hyperinsulinemia has the potential to modulate leptin levels beyond what can be explained by total adiposity. Moreover, this relation also seems to exist in a dynamic setting (i.e. during weight loss) because changes in insulin were independent predictors of the changes in leptinemia in both men and women after correction for changes in FM.

Adipose Tissue↗
PubMed2000

Changes in energy expenditure and substrate oxidation resulting from weight loss in obese men and women: is there an important contribution of leptin?

The aim of the present study was to determine the impact of weight loss and its related metabolic and hormonal changes on resting energy expenditure (REE) and substrate oxidation. Forty subjects (16 men and 24 women) took part in a 15-week weight loss program that consisted of drug therapy (fenfluramine, 60 mg/day) or placebo coupled to an energy restriction (-700 Cal/day). Subjects were asked to come to the laboratory after an overnight fast for an indirect calorimetry measurement before and after weight loss. Fasting blood samples were also drawn and were analyzed for plasma glucose, insulin, leptin, and free fatty acid determinations. This program reduced body weight by 11% and 9% (P < 0.01) in men and women, respectively. Fat mass (FM) and fat-free mass (FFM) were also significantly reduced in both sexes. A significant decrease in REE (13%; P < 0.01) and fat oxidation (11%; P = 0.08) was observed in men in response to this program, whereas no significant differences were noted for these variables in women. In men, positive correlations were found between changes in FFM and energy-related variables, whereas the best predictor of changes in REE and substrate oxidation was the change in FM in women. The most important finding of this study is that in men, the association between changes in fasting plasma leptin and changes in REE (r = 0.50; P < 0.01) and fat oxidation (r = 0.63; P < 0.01) persist after correction for changes in body composition. These results suggest that a comparable weight loss is accompanied by a greater decrease in REE and substrate oxidation in men than in women, and that these changes are better explained by changes in leptinemia in men and by changes in FM in women.

Adult↗
PubMed1999

Physical activity and low-fat diet: is it enough to maintain weight stability in the reduced-obese individual following weight loss by drug therapy and energy restriction?

OBJECTIVE: The anthropometric and physiological effects of a physical activity (PA) and a mildly energy-restricted low-fat diet (LFD) follow-up program after a long-term dietary restriction were studied in 12 men and 8 women. RESEARCH METHODS AND PROCEDURES: The dietary restriction (approximately 700 kcal/day) was accompanied by a fenfluramine (60 mg/day) or placebo treatment for 15 weeks, whereas the mean duration of the PA-LFD follow-up was 18 weeks. RESULTS: The long-term dietary restriction reduced body weight (-11.9 and -7.6 kg, p<.001), fat mass (FM) (-10.6 and -5.8 kg, p<0.01), resting metabolic rate (RMR) (-304 kcal/day, p<0.01 and -148 kcal/day, NS) in men and women, respectively. A decrease in fat-free mass (FFM) was also observed in women (-1.8 kg, p<0.05). The PA-LFD follow-up preserved weight stability at a reduced body weight and caused an additional significant decrease in FM for men (-3.4 kg, p<0.05). This part of the intervention also caused an increase in daily RMR for men (134 kcal/day, NS) to the point where this value no longer differed from the pre-energy restriction value. In contrast, RMR was further reduced in women (-200 kcal/day) to the point where it significantly differed from initial values (p<0.01). Resting seated heart rate was reduced by the PA-LFD follow-up in men leading it to differ significantly from both pre- and post-energy restriction values (-8.5 and -5.5 bpm, p<0.01). DISCUSSION: In conclusion, these results suggest that a PA-LFD follow-up has the potential to permit body weight stability and may even accentuate fat loss in the reduced-obese state. Moreover, resting energy expenditure is increased under such conditions in men. These stimulating effects seem to be specific to energy metabolism since seated heart rate was either further reduced or remained stable in response to the PA-LFD follow-up.

Adult↗