The Effect of CYP19 and COMT Polymorphisms on Exercise‐Induced Fat Loss in Postmenopausal Women

Objective:To examine whether genetic polymorphisms in CYP19 [intron 4 (TTTA)_n; n = 7 to 13 and a 3‐base pair deletion, which is in strong linkage disequilibrium with the seven repeat] and COMT (Val^108/158Met) modified the change in BMI, total and percentage body fat, or subcutaneous and intra‐abdominal fat during a year‐long exercise intervention trial. These genes metabolize estrogens and androgens, which are important in body fat regulation. Research Methods and Procedures: A randomized intervention trial was used, with an intervention goal of 225 min/wk of moderate‐intensity exercise for one year. Participants (n = 173) were postmenopausal, 50 to 75 years old, sedentary, overweight or obese, and not taking hormone therapy at baseline. Results: Exercisers with two vs. no CYP19 11‐repeat alleles had a larger decrease in total fat (?3.1 kg vs. ?0.5 kg, respectively, p = 0.01) and percentage body fat (?2.4% vs. ?0.6%, respectively, p = 0.001). Exercisers with the COMT Met/Met vs. Val/Val genotype had a smaller decrease in percentage fat (?0.7% vs. ?1.9%, respectively, p = 0.05). Among exercisers, women with the COMT Val/Val genotype and at least one copy of the CYP19 11‐repeat allele vs. those with neither genotype/allele had a significantly larger decrease in BMI (?1.0 vs. +0.1 kg/m², respectively, p = 0.009), total fat (?2.9 vs. ?0.5 kg, respectively, p = 0.004), and percentage body fat (?2.6% vs. ?0.4%, respectively, p < 0.001). Discussion: Genetic polymorphisms in CYP19 and COMT may be important for body fat regulation and possibly modify the effect of exercise on fat loss in postmenopausal women.     

Effects of Exercise on Metabolic Risk Variables in Overweight Postmenopausal Women: A Randomized Clinical Trial

Objective: This study examined the effects of exercise on metabolic risk variables insulin, leptin, glucose, and triglycerides in overweight/obese postmenopausal women. Research Methods and Procedures: Sedentary women (n = 173) who were overweight or obese (BMI ≥ 25 kg/m² or ≥24 kg/m² with ≥33% body fat), 50 to 75 years of age, were randomized to 12 months of exercise (≥45 minutes of moderate‐intensity aerobic activity 5 d/wk) or to a stretching control group. Body composition (DXA) and visceral adiposity (computed tomography) were measured at baseline and 12 months. Insulin, glucose, triglycerides, and leptin were measured at baseline and 3 and 12 months. Insulin resistance was evaluated by the homeostasis model assessment formula. Differences from baseline to follow‐up were calculated and compared across groups. Results: Exercisers had a 4% decrease and controls had a 12% increase in insulin concentrations from baseline to 12 months (p = 0.0002). Over the same 12‐month period, leptin concentrations decreased by 7% among exercisers compared with remaining constant among controls (p = 0.03). Homeostasis model assessment scores decreased by 2% among exercisers and increased 14% among controls from baseline to 12 months (p = 0.0005). The exercise effect on insulin was modified by changes in total fat mass (trend, p = 0.03), such that the exercise intervention abolished increases in insulin concentrations associated with gains in total fat mass. Discussion: Regular moderate‐intensity exercise can be used to improve metabolic risk variables such as insulin and leptin in overweight/obese postmenopausal women. These results are promising for health care providers providing advice to postmenopausal women for lifestyle changes to reduce risk of insulin resistance, coronary heart disease, and diabetes.     

Dose-dependent effects of training and detraining on weight in 6406 runners during 7.4 years

Objective: Prior randomized and non‐randomized training studies have failed to establish a dose‐response relationship between vigorous exercise and weight loss; this failure may be due, in part, to their short durations and small sample sizes. The objectives of this study were to determine whether exercise reduces body weight and to examine the dose‐response relationships between changes in exercise and changes in total and regional adiposity. Research Methods and Procedures: This was a large prospective study of 3973 men and 1444 women who quit running (detraining), 270 men and 146 women who started running (training), and 420 men and 153 women who remained sedentary during 7.4 years of follow‐up. The outcomes measured were weekly running distance, body weight, BMI, body circumferences, and bra cup size. Results: There were significant inverse relationships between the changes in the amount of vigorous exercise (km/wk run) and the changes in weight and BMI in men (slope ± standard error: ?0.039 ± 0.005 kg/km per week and ?0.012 ± 0.002 kg/m² per km/wk, respectively) and in older women (?0.060 ± 0.018 kg/km per week and ?0.022 ± 0.007 kg/m² per km/wk) who quit running, and in initially sedentary men (?0.098 ± 0.017 kg/km per week and ?0.032 ± 0.005 kg/m² per km/wk) and women (?0.062 ± 0.023 kg/km per week and ?0.021 ± 0.008 kg/m² per km/wk) who started running. Changes in waist circumference, an indicator of intra‐abdominal fat, were also inversely related to changes in running distance in men who quit (?0.026 ± 0.005 cm/km per week) or started running (?0.078 ± 0.017 cm/km per week). Discussion: The initiation of vigorous exercise and its cessation decrease and increase, respectively, body weight and intra‐abdominal fat, and these changes are proportional to the change in exercise dose.     

Metabolic Syndrome and Changes in Body Fat From a Low‐fat Diet and/or Exercise Randomized Controlled Trial

It is difficult to identify the successful component(s) related to changes in metabolic syndrome (MetS) from lifestyle interventions: the weight loss, the behavior change, or the combination. The purpose of this study is to determine the effects of a weight‐stable randomized controlled trial of low‐fat diet and exercise, alone and in combination, on MetS. Men (n = 179) and postmenopausal women (n = 149) with elevated low‐density lipoprotein cholesterol (LDL‐C) and low high‐density lipoprotein cholesterol (HDL‐C) were randomized into a 1‐year, weight‐stable trial with four treatment groups: control (C), diet (D), exercise (E), or diet plus exercise (D+E). MetS was defined using a continuous score. Changes in MetS score (ΔMetS) were compared between groups using analysis of covariance, stratified by gender and using two models, with and without baseline and change in percent body fat (ΔBF) as a covariate. In men, ΔMetS was higher for D vs. C (P = 0.04), D+E vs. C (P = 0.0002), and D+E vs. E (P = 0.02). For women, ΔMetS was greater for D vs. C (P = 0.045), E vs. C (P = 0.02), and D+E vs. C (P = 0.004). After adjusting for ΔBF, all differences between groups were attenuated and no longer significant. ΔMetS were associated with ΔBF for both men (P < 0.0001) and women (P = 0.004). After adjustment for ΔBF, low‐fat diet alone and in combination with exercise had no effect on MetS. The key component for MetS from low‐fat diet and/or increased physical activity appears to be body fat loss.     

The effect of pioglitazone and resistance training on body composition in older men and women undergoing hypocaloric weight loss

Age‐related increases in ectopic fat accumulation are associated with greater risk for metabolic and cardiovascular diseases, and physical disability. Reducing skeletal muscle fat and preserving lean tissue are associated with improved physical function in older adults. PPARγ‐agonist treatment decreases abdominal visceral adipose tissue (VAT) and resistance training preserves lean tissue, but their effect on ectopic fat depots in nondiabetic overweight adults is unclear. We examined the influence of pioglitazone and resistance training on body composition in older (65–79 years) nondiabetic overweight/obese men (n = 48, BMI = 32.3 ± 3.8 kg/m²) and women (n = 40, BMI = 33.3 ± 4.9 kg/m²) during weight loss. All participants underwent a 16‐week hypocaloric weight‐loss program and were randomized to receive pioglitazone (30 mg/day) or no pioglitazone with or without resistance training, following a 2 × 2 factorial design. Regional body composition was measured at baseline and follow‐up using computed tomography (CT). Lean mass was measured using dual X‐ray absorptiometry. Men lost 6.6% and women lost 6.5% of initial body mass. The percent of fat loss varied across individual compartments. Men who were given pioglitazone lost more visceral abdominal fat than men who were not given pioglitazone (?1,160 vs. ?647 cm³, P = 0.007). Women who were given pioglitazone lost less thigh subcutaneous fat (?104 vs. ?298 cm³, P = 0.002). Pioglitazone did not affect any other outcomes. Resistance training diminished thigh muscle loss in men and women (resistance training vs. no resistance training men: ?43 vs. ?88 cm³, P = 0.005; women: ?34 vs. ?59 cm³, P = 0.04). In overweight/obese older men undergoing weight loss, pioglitazone increased visceral fat loss and resistance training reduced skeletal muscle loss. Additional studies are needed to clarify the observed gender differences and evaluate how these changes in body composition influence functional status.     

Weight loss strategies for obese adults: personalized weight management program vs. standard care

Objective: The objective of this study was to evaluate the effect of a 32‐week personalized Polar weight management program (PWMP) compared with standard care (SC) on body weight, body composition, waist circumference, and cardiorespiratory fitness in overweight or obese adults. Research Methods and Procedures: Overweight or obese (29 ± 2 kg/m²) men and women (n = 74) 38 ± 5 years of age were randomly assigned into either PWMP (men = 20, women = 21) or SC (men = 15, women = 18). Both groups managed their own diet and exercise program after receiving the same standardized nutrition and physical activity advice. PWMP also received a weight management system with literature to enable the design of a personalized diet and exercise weight loss program. Body weight and body composition, waist circumference, and cardiorespiratory fitness were measured at weeks 0, 16, and 32. Results: Eighty percent of participants completed the 32‐week intervention, with a greater proportion of the dropouts being women (PWMP: 2 men vs. 7 women; SC: 2 men vs. 4 women). At 32 weeks, PWMP completers had significantly (p < 0.001) greater losses in body weight [6.2 ± 3.4 vs. 2.6 ± 3.6 (standard deviation) kg], fat mass (5.9 ± 3.4 vs. 2.2 ± 3.6 kg), and waist circumference (4.4 ± 4.5 vs. 1.0 ± 3.6 cm). Weight loss and fat loss were explained by the exercise energy expenditure completed and not by weekly exercise duration. Discussion: More effective weight loss was achieved after treatment with the PWMP compared with SC. The results suggest that the PWMP enables effective weight loss through tools that support self‐monitoring without the requirement of more costly approaches to program supervision.     

Exercise‐Induced Reduction in Obesity and Insulin Resistance in Women: a Randomized Controlled Trial

Objectives : To determine the effects of equivalent diet‐ or exercise‐induced weight loss and exercise without weight loss on subcutaneous fat, visceral fat, and insulin sensitivity in obese women. Research Methods and Procedures : Fifty‐four premenopausal women with abdominal obesity [waist circumference 110.1 ± 5.8 cm (mean ± SD)] (BMI 31.3 ± 2.0 kg/m²) were randomly assigned to one of four groups: diet weight loss (n = 15), exercise weight loss (n = 17), exercise without weight loss (n = 12), and a weight‐stable control group (n = 10). All groups underwent a 14‐week intervention. Results : Body weight decreased by ～6.5% within both weight loss groups and was unchanged in the exercise without weight loss and control groups. In comparison with controls, cardiorespiratory fitness improved within the exercise groups only (p < 0.01). Reduction in total, abdominal, and abdominal subcutaneous fat within the exercise weight loss group was greater (p < 0.001) than within all other groups. The reduction in total and abdominal fat within the diet weight loss and exercise without weight loss groups was greater than within controls (p < 0.001) but not different from each other (p > 0.05). Visceral fat decreased within all treatment groups (p < 0.008), and these changes were not different from each other. In comparison with the control group, insulin sensitivity improved within the exercise weight loss group alone (p < 0.001). Discussion : Daily exercise without caloric restriction was associated with substantial reductions in total fat, abdominal fat, visceral fat, and insulin resistance in women. Exercise without weight loss was also associated with a substantial reduction in total and abdominal obesity.     

Exercise Improves Body Fat,Lean Mass,and Bone Mass in Breast Cancer Survivors

Given the negative effects of a breast cancer diagnosis and its treatments on body weight and bone mass, we investigated the effects of a 6‐month randomized controlled aerobic exercise intervention vs. usual care on body composition in breast cancer survivors. Secondary aims were to examine the effects stratified by important prognostic and physiologic variables. Seventy‐five physically inactive postmenopausal breast cancer survivors were recruited through the Yale–New Haven Hospital Tumor Registry and randomly assigned to an exercise (n = 37) or usual care (n = 38) group. The exercise group participated in 150 min/week of supervised gym‐ and home‐based moderate‐intensity aerobic exercise. The usual care group was instructed to maintain their current physical activity level. Body composition was assessed at baseline and 6‐months through dual‐energy X‐ray absorptiometry (DXA) by one radiologist blinded to the intervention group of the participants. On an average, exercisers increased moderate‐intensity aerobic exercise by 129 min/week over and above baseline levels compared with 45 min/week among usual care participants (P < 0.001). Exercisers experienced decreases in percent body fat (P = 0.0022) and increases in lean mass (P = 0.047) compared with increases in body fat and decreases in lean mass in usual care participants. Bone mineral density (BMD) was also maintained among exercisers compared with a loss among usual care participants (P = 0.043). In summary, moderate‐intensity aerobic exercise, such as brisk walking, produces favorable changes in body composition that may improve breast cancer prognosis.     

Cardiorespiratory fitness influences the blood pressure response to experimental weight gain

Objective: We tested the hypothesis that with similar weight gain the increase in blood pressure (BP) would be smaller in men with higher cardiorespiratory fitness (HCRF) than in men with lower cardiorespiratory fitness (LCRF). Research Methods and Procedures: Thirteen men (age = 23 ± 1, BMI = 24 ± 1) were overfed by ～1000 kcal/d over ～8 weeks to achieve a 5‐kg weight gain. Resting BP and 24‐hour ambulatory BP, body composition, and fat distribution were measured. Results: Cardiorespiratory fitness (CRF) was higher in the HCRF group compared with the LCRF group (49.9 ± 1.2 vs. 38.1 ± 1.4 mL/kg per minute, p < 0.001). At baseline, body weight was similar in the HCRF and LCRF groups, whereas the HCRF group displayed lower levels of total body fat (13.0 ± 1.7 vs. 16.9 ± 1.3 kg, p = 0.049) and abdominal visceral fat (49 ± 6 vs. 80 ± 14 cm², p = 0.032). Resting BP and 24‐hour ambulatory BP were similar in the two groups at baseline. After weight gain, body weight increased ～5 kg (p < 0.05) in both groups; the changes in body composition and regional fat distribution were similar. As hypothesized, the increases in resting systolic (1 ± 2 vs. 7 ± 2 mm Hg; p = 0.008) and diastolic (?1 ± 4 vs. 5 ± 1 mm Hg; p = 0.005) BP were smaller in the HCRF group. CRF was correlated with the increases in resting systolic (r = ?0.64; p = 0.009) and diastolic BP (r = ?0.80; p < 0.001). Furthermore, the relationship between CRF and BP remained significant after adjusting for the changes in the proportion of total abdominal fat gained as visceral fat. Discussion: These findings suggest that higher levels of CRF are associated with a smaller increase in BP with weight gain, independently of changes in abdominal visceral fat.     

FTO Genotype and the Weight Loss Benefits of Moderate Intensity Exercise

The fat mass and obesity‐associated (FTO) gene was genotyped for the participants in the Dose‐Response to Exercise in postmenopausal Women (DREW) trial and analyses were performed to determine whether an FTO variant was associated with adiposity and cardiorespiratory fitness (CRF) before and after 6 months of moderate intensity exercise in white women (n = 234). The A/A homozygotes for rs8050136 had a higher BMI (kg/m²) compared to C/C homozygotes at baseline (32.8 (0.6) vs. 31.0 (0.4), respectively; P < 0.05) and at follow‐up (31.9 (0.6) vs. 30.4 (0.5), respectively; P < 0.05). Weight loss occurred after exercise, but there was no significant genotype by exercise interaction over time. Exploratory analyses among women exposed to moderate intensity exercise meeting, or exceeding, the physical activity recommendation found that those homozygous A/A lost significantly more weight than the C allele carriers (?3.3 (0.7) kg vs. ?1.4 (0.4) kg and ?1.5 (0.5) kg, respectively; P < 0.05). CRF, defined as VO_2peak (oxygen consumption), increased after exercise and the magnitude of the increase was similar for each genotype. In conclusion, women genetically predisposed to being obese experienced weight loss and CRF benefits with moderate intensity exercise, with additional weight loss observed when the women met or exceeded the physical activity recommendations.     

Adiponectin and ghrelin levels and body size in normoglycemic Filipino, African-American, and white women

Objective: Prior studies have reported ethnic differences in adiponectin and ghrelin, but few have assessed the role of body size in normoglycemic women. We compared fasting adiponectin and ghrelin concentrations in normoglycemic 40‐ to 80‐year‐old Filipino, African‐American, and white women. Methods: Participants included women from the Rancho Bernardo Study (n = 143), the University of California‐San Diego Filipino Women's Health Study (n = 136), and the Health Assessment Study of African‐American Women (n = 212). A 2‐hour oral glucose tolerance test was administered; glucose, insulin, lipid, and anthropometric measurements were obtained. Fasting adiponectin and ghrelin were measured by radioimmunoassay. Results: Whites and Filipinas had similar BMI (23.7 and 24.3 kg/m², respectively), waist girth (75.6 and 77.2 cm, respectively), and total body fat (27.4 and 28.5%, respectively); African‐Americans had significantly larger BMI (28.8 kg/m²), waist girth (86.3 cm), and body fat (39.6%, p < 0.0001). Adiponectin was lower in Filipinas (8.90 µg/mL) and African‐Americans (9.67 µg/mL) compared with whites (15.6 µg/mL, p < 0.001) after adjusting for age, homeostasis model assessment of insulin resistance (HOMA‐IR), and waist‐to‐hip ratio. Compared with whites, Filipinas (β = ?5.06, p < 0.0001) and African‐Americans (β = ?6.85, p < 0.0001) had significantly lower adiponectin levels after adjusting for age, waist‐to‐hip ratio, HOMA‐IR, triglycerides, high‐density lipoprotein (HDL) cholesterol, exercise, and alcohol use. Ghrelin was significantly lower in Filipinas compared with African‐Americans (1146.9 vs. 1412.2 pg/mL, p < 0.001), and this observation persisted in multivariable analysis (β = ?245.4, p < 0.0001). Ghrelin levels did not differ between whites (1356.9 pg/mL) and either ethnic group. Discussion: Normoglycemic Filipino and African‐American women had significantly lower adiponectin concentrations than white women, and Filipinas had lower ghrelin levels than African‐Americans, independently of body size or indices of insulin resistance or lipids.     

Ghrelin Does Not Influence Gastric Emptying in Obese Subjects

Objective: To evaluate the relationship between fasting plasma concentrations of ghrelin and gastric emptying in obese individuals compared with lean subjects. Research Methods and Procedures: We included 20 obese patients (9 men and 11 women, BMI > 30 kg/m²) and 16 nonobese control subjects (7 men and 9 women, BMI ≤ 25 kg/m²). Gastric emptying of solids (egg sandwich labeled with radionuclide) was measured at 120 minutes with (99m)Tc‐single photon emission computed tomography imaging. Ghrelin and leptin were analyzed by radioimmunoassay and ELISA methods, respectively. Results: The gastric half‐emptying time was similar in obese men and women (67.8 ± 14.79 vs. 66.6 ± 13.56 minutes) but significantly shorter (p < 0.001) than in the control population (men: 88.09 ± 11.72 minutes; women: 97.25 ± 10.31 minutes). Ghrelin levels were significantly lower in obese subjects (131.37 ± 47.67 vs. 306.3 ± 45.52 pg/mL; p < 0.0001 in men and 162.13 ± 32.95 vs. 272.8 ± 47.77 pg/mL; p < 0.0001 in women). A negative correlation between gastric emptying and fasting ghrelin levels was observed only in lean subjects (y = ?0.2391x + 157.9; R² = 0.95). Also, in the lean group, ghrelin was the only significant independent determinant of gastric emptying, explaining 98% of the variance (adjusted R²) in a multiple regression analysis. Discussion: This report shows that, in humans, gastric emptying is faster in obese subjects than in lean controls and that, whereas ghrelin is the best determinant of gastric kinetics in healthy controls, this action is lost in obesity.     

Insulin Resistance in Nondiabetic Morbidly Obese Patients: Effect of Bariatric Surgery

Objective: To evaluate insulin action on substrate use and insulinemia in nondiabetic class III obese patients before and after weight loss induced by bariatric surgery. Research Methods and Procedures: Thirteen obese patients (four men/nine women; BMI = 56.3 ± 2.7 kg/m²) and 13 lean subjects (five men/eight women; BMI = 22.4 ± 0.5 kg/m²) underwent euglycemic clamp, oral glucose tolerance test, and indirect calorimetry. The study was carried out before (Study I) and after (～40% relative to initial body weight; Study II) weight loss induced by Roux‐en‐Y Gastric bypass with silastic ring surgery. Results: The obese patients were insulin resistant (whole‐body glucose use = 19.7 ± 1.5 vs. 51.5 ± 2.4 μmol/min per kilogram fat‐free mass, p < 0.0001) and hyperinsulinemic in the fasting state (332 ± 86 vs. 85 ± 5 pM, p < 0.0001) and during the oral glucose tolerance test compared with the lean subjects. Fasting plasma insulin normalized after weight loss, whereas whole‐body glucose use increased (35.5 ± 3.7 μmol/min per kilogram fat‐free mass, p < 0.05 vs. Study I). The higher insulin clearance of obese did not change during the follow‐up period. Insulin‐induced glucose oxidation and nonoxidative glucose disposal were lower in the obese compared with the lean group (all p < 0.05). In Study II, the former increased slightly, whereas nonoxidative glucose disposal reached values similar to those of the control group. Fasting lipid oxidation was higher in the obese than in the control group and did not change significantly in Study II. The insulin effect on lipid oxidation was slightly improved (p = 0.01 vs. Study I). Discussion: The rapid weight loss after surgery in obese class III patients normalized insulinemia and improved insulin sensitivity almost entirely due to glucose storage, whereas fasting lipid oxidation remained high.     

Increased resting energy expenditure after 40 minutes of aerobic but not resistance exercise

Objective: Resting energy expenditure (REE) is increased 24 hours after high‐intensity aerobic exercise lasting 60 minutes, whereas results have been inconsistent after resistance training and aerobic exercise of shorter duration. The objective of the study was to compare the effects of 40 minutes of high‐intensity aerobic vs. resistance exercise on REE 19 to 67 hours after exercise. Research Methods and Procedures: REE was compared 19, 43, and 67 hours after 40 minutes of aerobic training (AT; 80% maximum heart rate) or resistance training (RT; 10 repetitions at 80% maximum strength, two sets and eight exercises). Twenty‐three black and 22 white women were randomly assigned to AT, RT, or no training (controls). Exercisers trained 25 weeks. REE was measured after a 12‐hour fast. Results: There was a significant time × group interaction for REE when adjusted for fat‐free mass and fat mass, with post hoc tests revealing that the 50‐kcal difference between 19 and 43 hours (1310 ± 196 to 1260 ± 161 kcal) and the 34‐kcal difference between 19 and 67 hours (1310 ± 196 to 1276 ± 168 kcal) were significant for AT. No other differences were found, including RT (19 hours, 1256 ± 160; 43 hours, 1251 ± 160; 67 hours, 1268 ± 188 kcal). Urine norepinephrine increased with training only in AT. After adjusting for fat‐free mass, REE Δ between 19 and both 43 and 67 hours was significantly related to urine norepinephrine (r = 0.76, p < 0.01 and 0.68, p < 0.03, respectively). Discussion: Consistent with findings on longer duration AT, these results show that 40 minutes of AT elevates REE for 19 hours in trained black and white women. This elevation did not occur with 40 minutes of RT. Results suggest that differences are, in part, due to increased sympathetic tone.     

Gender Differences in Lipoprotein Lipase Activity after Acute Exercise

Objective: To determine whether gender differences exist in lipoprotein lipase (LPL) activity in response to exercise and/or insulin. Exercise and insulin are known modulators of LPL activity in men, but this is less clear in women. LPL activity may predict propensity for obesity; therefore, understanding its modulators is of considerable importance. Research Methods and Procedures: Gender differences in skeletal muscle and adipose tissue LPL activity were determined after a single bout of exercise followed by a hyperinsulinemic/euglycemic clamp and compared with an identical rest day in healthy lean men (n = 10) and women (n = 10). Muscle and adipose tissue biopsies were obtained pre‐ (post‐exercise vs. rest) and post‐clamp. Results: Basal levels of muscle and adipose tissue LPL activity were not different between men and women. There was, however, a significant gender by day interaction for muscle LPL activity (p = 0.023) and adipose tissue LPL activity (p = 0.013). In muscle, this was because of a significant increase in LPL activity on the exercise vs. rest day in men (p < 0.001) but not women. Adipose tissue LPL activity also increased significantly in men on the exercise day relative to rest day (p = 0.04) but decreased in women (p = 0.10). The hyperinulinemic/euglycemic clamp had no independent effect on tissue LPL activity, in either gender, after rest or exercise. Discussion: In the 3 to 4 hours after exercise, muscle and adipose tissue LPL activity increased significantly in men, whereas LPL activity remained unchanged in women.     

Effects of Obesity and Body Fat Distribution on Lipids and Lipoproteins in Nondiabetic American Indians: The Strong Heart Study

Objectives: To examine the relationship between obesity and lipoprotein profiles and compare the effects of total obesity and central adiposity on lipids/lipoproteins in American Indians. Research Methods and Procedures: Participants were 773 nondiabetic American Indian women and 739 men aged 45 to 74 years participating in the Strong Heart Study. Total obesity was estimated using body mass index (BMI). Central obesity was measured as waist circumference. Lipoprotein measures included triglycerides, high‐density lipoprotei in (HDL) cholesterol, low‐density lipoprotein (LDL) cholesterol, apolipoprotein AI (apoAI), and apolipoprotein B (apoB). Partial and canonical correlation analyses were used to examine the associations between obesity and lipids/lipoproteins. Results: Women were more obese than men in Arizona (median BMI 32.1 vs. 29.2 kg/m²) and South Dakota and North Dakota (28.3 vs. 28.0 kg/m²), but there was no sex difference in waist circumference. Men had higher apoB and lower apoAI levels than did women. In women, when adjusted for center, gender, and age, BMI was significantly related to HDL cholesterol (r = ?0.24, p < 0.001). There was a significant but weak relation with apoAI (r = ?0.14 p < 0.001). Waist circumference was positively related to triglycerides (r = 0.14 p < 0.001) and negatively related to HDL cholesterol (r = ?0.23, p < 0.001) and apoAI (r = ?0.13, p < 0.001). In men, BMI was positively correlated with triglycerides (r = 0.30, p < 0.001) and negatively correlated with HDL cholesterol (r = ?0.35, p < 0.001) and apoAI (r = ?0.23, p < 0.001). Triglycerides increased with waist circumference (r = 0.30, p < 0.001) and HDL cholesterol decreased with waist circumference (r = ?0.36 p < 0.001). In both women and men there was an inverted U‐shaped relationship between obesity and waist with LDL cholesterol and apoB. In canonical correlation analysis, waist circumference received a greater weight (0.86) than did BMI (0.17) in women. However, the canonical weights were similar for waist (0.46) and BMI (0.56) in men. Only HDL cholesterol (?1.02) carried greater weight in women, whereas in men, triglycerides (0.50), and HDL cholesterol (?0.64) carried a large amount of weight. All the correlation coefficients between BMI, waist circumference, and the first canonical variable of lipids/lipoproteins or between the individual lipid/lipoprotein variables and the first canonical variable of obesity were smaller in women than in men. Triglycerides and HDL cholesterol showed clinically meaningful changes with BMI and waist circumference in men. All lipid/lipoprotein changes in women in relation to BMI and waist circumference were minimal. Discussion: The main lipoprotein abnormality related to obesity in American Indians was decreased HDL cholesterol, especially in men. Central adiposity was more associated with abnormal lipid/lipoprotein profiles than general obesity in women; both were equally important in men.     

Higher protein intake preserves lean mass and satiety with weight loss in pre-obese and obese women

Objective: To examine the effects of dietary protein and obesity classification on energy‐restriction‐induced changes in weight, body composition, appetite, mood, and cardiovascular and kidney health. Research Methods and Procedures: Forty‐six women, ages 28 to 80, BMI 26 to 37 kg/m², followed a 12‐week 750‐kcal/d energy‐deficit diet containing higher protein (HP, 30% protein) or normal protein (NP, 18% protein) and were retrospectively subgrouped according to obesity classification [pre‐obese (POB), BMI = 26 to 29.9 kg/m²; obese (OB), BMI = 30 to 37 kg/m²). Results: All subjects lost weight, fat mass, and lean body mass (LBM; p < 0.001). With comparable weight loss, LBM losses were less in HP vs. NP (?1.5 ± 0.3 vs. ?2.8 ± 0.5 kg; p < 0.05) and POB vs. OB (?1.2 ± 0.3 vs. ?2.9 ± 0.4 kg; p < 0.005). The main effects of protein and obesity on LBM changes were independent and additive; POB‐HP lost less LBM vs. OB‐NP (p < 0.05). The energy‐restriction‐induced decline in satiety was less pronounced in HP vs. NP (p < 0.005). Perceived pleasure increased with HP and decreased with NP (p < 0.05). Lipid‐lipoprotein profile and blood pressure improved and kidney function minimally changed with energy restriction (p < 0.05), independently of protein intake. Discussion: Consuming a higher‐protein diet and accomplishing weight loss before becoming obese help women preserve LBM. Use of a higher‐protein diet also improves perceptions of satiety and pleasure during energy restriction.     

Obesity and Sarcopenia after Menopause Are Reversed by Sex Hormone Replacement Therapy

Objective: Menopause is linked to an increase in fat mass and a decrease in lean mass exceeding age‐related changes, possibly related to reduced output of ovarian steroids. In this study we examined the effect of combined postmenopausal hormone replacement therapy (HRT) on the total and regional distribution of fat and lean body mass. Research Methods and Procedures: Sixteen healthy postmenopausal women (age: 55 ± 3 years) were studied in a placebo‐controlled, crossover study and were randomized to 17β estradiol plus cyclic norethisterone acetate (HRT) or placebo in two 12‐week periods separated by a 3‐month washout. Total and regional body composition was measured by DXA at baseline and in the 10th treatment week in both periods. Changes were compared by a paired Student's t test. Results: The change in body weight during HRT was equal to the change during placebo (?24.6 g vs. ?164 g, p = 0.42), but relative fat mass was significantly reduced (?0.5% vs. +1.24%, p < 0.01). During HRT, compared with during placebo, lean body mass increased (+347 g vs. ?996 g, p < 0.01) and total fat mass decreased (?400 g vs. +836 g, p = 0.06). Total bone mineral content increased (+28.9 g vs. ?4.4 g, p = 0.04) and abdominal fat decreased (?185 g vs. +253 g, p = 0.04) during HRT compared with placebo. Discussion: HRT is linked to the reversal of both menopause‐related obesity and loss of lean mass, without overall change in body weight. The increase in lean body mass during HRT is likely explained by muscle anabolism, which in turn, prevents disease in the elderly.     

Randomized trial of a multifaceted commercial weight loss program

Objective: To test whether a commercial weight loss program promotes greater weight loss in overweight or obese women compared with control conditions and to describe the effect on plasma lipids, carotenoids, hormones, and fitness. Research Methods and Procedures: Overweight or obese women were randomized to commercial weight loss program or control conditions (n = 35 each). Results: At randomization, participants were 41.1 (11.4) (mean [standard deviation]) years, BMI 34.0 (3.5) kg/m², and weight 92.0 (11.1) kg. At 6 months, change in weight by intent‐to‐treat (ITT) analysis was ?7.2 (6.7) kg and ?7.8% (7.2%) in the intervention group vs. ?0.3 (3.9) kg and ?0.3% (4.5%) in the control group (n = 35 for each; p < 0.01). One‐year ITT analysis revealed significantly greater change in weight, percent weight, BMI, and waist and hip circumferences in the intervention vs. control group. Completers at 1 year exhibited change in weight of ?7.3 (10.4) kg for the intervention group (n = 32) vs. ?0.7 (5.6) kg for controls (n = 33) (p < 0.01), and ?7.8% (11.1%) weight change for the intervention group vs. ?0.7% (6.2%) for controls (p < 0.01). High‐density lipoprotein (HDL) cholesterol concentration increased significantly in the intervention group. Fasting serum insulin decreased in the intervention but increased in the control group at 6 months (p < 0.01), remaining different at 1 year (p = 0.05). Discussion: The commercial program successfully facilitated weight loss, which was notably maintained at 1 year, and promoted favorable changes in plasma lipid and hormone concentrations.     

Influence of Sibutramine on Energy Expenditure in African American Women

Objective: African American women have a high prevalence of obesity, which partially may be explained by their lower rates of resting energy expenditure (REE). The aim of this study was to examine the influence of acute sibutramine administration on REE and post‐exercise energy expenditure in African American women. Research Methods and Procedures: A total of 15 premenopausal, African American women (age, 29 ± 5 years; body fat, 38 ± 7%) completed a randomized, double‐blind cross‐over design with a 30‐mg ingestion of sibutramine or a placebo. Each trial was completed a month apart in the follicular phase and included a 30‐minute measurement of REE 2.5 hours after sibutramine or placebo administration. This was followed by 40 minutes of cycling at ～70% of peak aerobic capacity and a subsequent 2‐hour measurement of post‐cycling energy expenditure. Results: There was no difference (p > 0.05) in REE (23.70 ± 2.81 vs. 23.69 ± 2.95 kcal/30 min), exercise oxygen consumption (1.22 ± 0.15 vs. 1.25 ± 0.15 liter/min), and post‐cycling energy expenditure (104.2 ± 12.7 vs. 104.9 ± 11.4 kcal/120 min) between the sibutramine and placebo trials, respectively. Cycling heart rate was significantly higher (p = 0.01) during the sibutramine (158 ± 14 beats/min) vs. placebo (150 ± 12 beats/min) trials. Discussion: These data demonstrate that acute sibutramine ingestion does not increase REE or post‐exercise energy expenditures but does increase exercising heart rate in overweight African American women. Sibutramine may, therefore, impact weight loss through energy intake and not energy expenditure mechanisms.