Effects of variation in protein and carbohydrate intake on body mass and composition during energy restriction: a meta-regression 1

BACKGROUND: It is unclear whether low-carbohydrate, high-protein, weight-loss diets benefit body mass and composition beyond energy restriction alone. OBJECTIVE: The objective was to use meta-regression to determine the effects of variations in protein and carbohydrate intakes on body mass and composition during energy restriction. DESIGN: English-language studies with a dietary intervention of > or =4200 kJ/d (1000 kcal/d), with a duration of > or =4 wk, and conducted in subjects aged > or =19 y were considered eligible for inclusion. A self-reported intake in conjunction with a biological marker of macronutrient intake was required as a minimum level of dietary control. A total of 87 studies comprising 165 intervention groups met the inclusion criteria. RESULTS: After control for energy intake, diets consisting of < or =35-41.4% energy from carbohydrate were associated with a 1.74 kg greater loss of body mass, a 0.69 kg greater loss of fat-free mass, a 1.29% greater loss in percentage body fat, and a 2.05 kg greater loss of fat mass than were diets with a higher percentage of energy from carbohydrate. In studies that were conducted for >12 wk, these differences increased to 6.56 kg, 1.74 kg, 3.55%, and 5.57 kg, respectively. Protein intakes of >1.05 g/kg were associated with 0.60 kg additional fat-free mass retention compared with diets with protein intakes < or =1.05 g/kg. In studies conducted for >12 wk, this difference increased to 1.21 kg. No significant effects of protein intake on loss of either body mass or fat mass were observed. CONCLUSION: Low-carbohydrate, high-protein diets favorably affect body mass and composition independent of energy intake, which in part supports the proposed metabolic advantage of these diets.     

Effects of exercise and food restriction on body composition and metabolic rate in obese women

Obese women (140-180% of ideal body weight) were studied on a metabolic ward during 1 wk of maintenance feeding, followed by 5 wk of 800 kcal/d (liquid formula diet). Five subjects participated in a supervised program of daily aerobic exercise and three subjects remained sedentary. Total weight loss was not different between exercising and nonexercising subjects but significantly more of the weight loss came from fat and less from fat-free mass in the exercising subjects. Resting metabolic rate (RMR) declined similarly in both groups (approximately 20%), even though exercising subjects were in greater negative energy balance due to the added energy cost of exercise. In summary, results from this controlled inpatient study indicate that exercise is beneficial when coupled with food restriction because it favors loss of body fat and preserves fat-free mass.     

Validation study of energy expenditure and intake during calorie restriction using doubly labeled water and changes in body composition

BACKGROUND: Clinical trials involving calorie restriction (CR) require an assessment of adherence to a prescribed CR with the use of an objective measure of energy intake (EI). OBJECTIVE: The objective was to validate the use of energy expenditure (EE) measured by doubly labeled water (DLW), in conjunction with precise measures of body composition, to calculate an individual's EI during 30% CR. DESIGN: Ten participants underwent 30% CR for 3 wk. During the last week (7 d), 24-h EE was measured in a respiratory chamber and simultaneously by DLW (EEDLW). EI was calculated from 7-d EE measured by DLW and from changes in energy stores (ES) (weight and body composition). Calculated EI was then compared with the actual EI measured in the chamber by using the following equations: calculated EI (kcal/d) = EEDLW + DeltaES, where DeltaESFM/FFM (kcal/d) = (9.3 x DeltaFM, g/d) + (1.1 x DeltaFFM, g/d), FM is fat mass, and FFM is fat-free mass. RESULTS: We found close agreement (R = 0.88) between EE measured in the metabolic chamber and EEDLW during CR. Using the measured respiratory quotient, we found that the mean (+/-SD) EE(DLW) was 1934 +/- 377 kcal/d and EE measured in the metabolic chamber was 1906 +/- 327 kcal/d, ie, a 1.3 +/- 8.9% overestimation. EI calculated from EEDLW and from changes in ES was 8.7 +/- 36.7% higher than the actual EI provided during the chamber stay (1596 +/- 656 kcal/d). CONCLUSIONS: DLW methods can accurately estimate 24-h EE during CR. Although the mean difference between actual and calculated EIs for the group was small, we conclude that the interindividual variability was too large to provide an assessment of CR adherence on an individual basis.     

Leptin and body composition in healthy postmenopausal women

BACKGROUND: Leptin has been proposed to be involved in central control of adiposity and fat distribution but the role of this peptide is controversial. The aim of our study was to test the relationship between serum leptin and body composition, fat distribution, and some biochemical markers such as fasting insulinemia and lipoproteins in a population of healthy Italian postmenopausal women. METHODS: One hundred and twenty-three postmenopausal women (62.1+/-8.7 years) were evaluated. Body composition (fat and lean mass) was assessed by dual-energy X-ray absorptiometry (DXA). Two regions of interest were determined for regional fat analysis. Serum leptin and insulinemia were measured by radioimmunoassay, lipoproteins with colorimetric methods and apolipoproteins nephelometrically. RESULTS: Plasma leptin levels are strongly related to total fat mass, in grams (r=0.73, p<0.001) or as a percentage of soft tissue (r=0.75, p<0.001), and to adiposity, calculated as ratio between lean and fat mass (r=0.76, p<0.001). A significant correlation was also found between serum leptin and central fat distribution (r=0.29, p<0.01). As concerns biochemical markers, serum leptin was significantly related to fasting insulin (r=0.38, p<0.001), total cholesterol (r=0.29, p<0.01), Apolipoprotein-B (r=0.35, p<0.001), and triglycerides (r=0.22, p<0.05). When corrected for total fat mass, the partial correlation coefficients remain significant for percentage of total body fat (r=0.27, p<0.01), adiposity (r=0.23, p<0.01), and fat proportion in android region (r=0.18, p<0.05). CONCLUSIONS: These data indicate that leptin levels are related to adiposity and fasting insulin levels; indeed fast insulin mantains significant correlation with leptin (r=0.23, p<0.01) after controlling for fat mass. Android distribution of fat mass in elderly women is associated with leptin concentration.     

Effect of nicotine patch on energy intake and weight gain in postmenopausal women during smoking cessation

IntroductionPost-cessation weight gain is a commonly cited barrier to smoking cessation. Some evidence suggests that nicotine replacement therapy may limit post-cessation weight gain by reducing energy intake. This project aims to assess differential changes in energy intake and body weight during smoking cessation in a sample of postmenopausal women randomized to receive 21 mg nicotine or placebo patch for 12 weeks.MethodsPostmenopausal women who smoked ≥ 10 cigarettes/day were enrolled in this double-blind randomized placebo-controlled study. Total energy intake (via four-day food diaries), body mass index (BMI; kg/m²), cigarettes/day and smoking status (self-report verified by exhaled carbon monoxide) were assessed at three time points: 2 weeks prior to quit date,12 weeks after quit date, and 12 months after smoking cessation treatment.ResultsParticipants (n = 119) were, on average, 55.8 ± 6.7 years old with a baseline BMI of 27.0 ± 5.2 and average cigarette/day was 21.1 ± 8.6. At Week 12, participants randomized to nicotine patch increased their mean caloric intake by 146.4 ± 547.7 kcal/day whereas those on placebo patch decreased their caloric intake by 175.3 ± 463.2 (f-value = 10.1, p-value = 0.002). Despite the differences in caloric intake, body weight remained similar between groups.ConclusionsThe results of this study indicate that nicotine patch may increase energy intake during treatment, and does not prevent post-cessation weight gain in postmenopausal smokers. Additional research is needed to replicate these findings and assess whether different forms of nicotine replacement therapy influence caloric intake and post-cessation weight gain in postmenopausal smokers.     

Flavonoid intake and cardiovascular disease mortality: a prospective study in postmenopausal women

BACKGROUND: Dietary flavonoids may have beneficial cardiovascular effects in human populations, but epidemiologic study results have not been conclusive. OBJECTIVE: We used flavonoid food composition data from 3 recently available US Department of Agriculture databases to improve estimates of dietary flavonoid intake and to evaluate the association between flavonoid intake and cardiovascular disease (CVD) mortality. DESIGN: Study participants were 34 489 postmenopausal women in the Iowa Women's Health Study who were free of CVD and had complete food-frequency questionnaire information at baseline. Intakes of total flavonoids and 7 subclasses were categorized into quintiles, and food sources were grouped into frequency categories. Proportional hazards rate ratios (RR) were computed for CVD, coronary heart disease (CHD), stroke, and total mortality after 16 y of follow-up. RESULTS: After multivariate adjustment, significant inverse associations were observed between anthocyanidins and CHD, CVD, and total mortality [RR (95% CI) for any versus no intake: 0.88 (0.78, 0.99), 0.91 (0.83, 0.99), and 0.90 (0.86, 0.95)]; between flavanones and CHD [RR for highest quintile versus lowest: 0.78 (0.65, 0.94)]; and between flavones and total mortality [RR for highest quintile versus lowest: 0.88 (0.82, 0.96)]. No association was found between flavonoid intake and stroke mortality. Individual flavonoid-rich foods associated with significant mortality reduction included bran (added to foods; associated with stroke and CVD); apples or pears or both and red wine (associated with CHD and CVD); grapefruit (associated with CHD); strawberries (associated with CVD); and chocolate (associated with CVD). CONCLUSION: Dietary intakes of flavanones, anthocyanidins, and certain foods rich in flavonoids were associated with reduced risk of death due to CHD, CVD, and all causes.     

Lipid and insulin concentrations in obese postmenopausal women: separate effects of energy restriction and weight loss.

The separate effects of energy restriction and weight loss on serum lipids were studied in 24 postmenopausal moderately obese women before and after weight loss of greater than 10 kg to normal weight. Fasting serum triglycerides (TGs), total cholesterol (TC), high-density-lipoprotein (HDL) and low-density-lipoprotein (LDL) cholesterol, and insulin were measured at the end of four 10-d in-hospital phases, two before and two after weight loss: phase I, stable weight; phase II, 3350 kJ/d(800 kcal/d), followed by outpatient weight loss; phase III, 3350 kJ/d (800 kcal/d); and phase IV, stable weight. Diet composition and exercise were constant the entire study. Energy-restriction effect was determined by comparing average values in stable-weight phases (I and IV) with low-energy phases (II and III); weight-loss effect was determined by comparing values in obese phases (I and II) with reduced-weight phases (III and IV). Energy restriction lowered TG, TC, LDL cholesterol, the LDL-HDL cholesterol ratio, and insulin and raised HDL cholesterol (all P less than 0.05). Weight loss lowered TG, TC, LDL cholesterol, and insulin (all P less than 0.01) but did not change HDL cholesterol or the LDL-HDL cholesterol ratio. The results suggest that reduction to a weight-steady nonobese state significantly lowers TG, TC, and LDL cholesterol but does not improve HDL cholesterol or the LDL-HDL cholesterol ratio.     

Resting metabolic rate and body composition of healthy Swedish women during pregnancy

Body weight, resting metabolic rate (RMR), total body potassium (TBK), and total body water were measured and total body fat (TBF) was calculated in a longitudinal study of 22 pregnant, healthy Swedish women. Measurements were made before pregnancy, at gestational weeks 16-18, 30, and 36, and 5-10 d and 6 mo postpartum. RMR increased more during pregnancy than previous estimates on well-nourished women showed and the increase was significantly correlated with the birth weight of the baby. TBK decreased during the first part of pregnancy; measurements at weeks 16-18 and 30 were significantly lower than the prepregnancy value and changes in TBK and RMR were significantly correlated. TBF gain during pregnancy was 5.8 +/- 4.0 kg and 60% was already gained by gestational weeks 16-18. Gain in fat was not correlated with birth weight.     

Moderate energy restriction increases bone resorption in obese postmenopausal women

BACKGROUND: Weight reduction reduces bone mineral density (BMD) and increases the risk of osteoporosis. OBJECTIVE: We investigated whether bone is mobilized in postmenopausal women during energy restriction and whether hormones regulate bone turnover and mass. DESIGN: Twenty-seven obese postmenopausal women with a mean (+/-SD) age of 55.9 +/- 7.9 y and body mass index (in kg/m(2)) of 33.0 +/- 3.8 completed the 6-mo study. Fourteen women followed a moderate energy-restricted diet (WL group) and 13 control subjects maintained their body weight (WM group). Body weight, bone turnover markers, serum parathyroid hormone (PTH), and dietary intake were measured throughout the study. Total-body BMD, sex hormone binding globulin, leptin, and estrone were measured at baseline and at week 25. RESULTS: In the WL group, body weight decreased by 10.2 +/- 5.5% (P < 0.001), body fat mass decreased by 18.7 +/- 11.3% (P < 0.001), and total-body BMD decreased by 1.2 +/- 1.2%; these changes were significantly different from those in the WM group (P < 0.05). Serial measurements showed chronically elevated rates of bone resorption and formation during energy restriction that were greater than in the WM group (P < 0.05). Serum sex hormone binding globulin increased and leptin decreased with weight loss (P < 0.05). Serum PTH tended to increase in the WL group but not in the WM group (P < 0.06). The reduction in fat mass with weight loss was directly associated with a decrease in serum estrone (P < 0.01, R(2) = 0.50). CONCLUSIONS: Moderate energy restriction increases bone turnover in obese postmenopausal women and may be regulated in part by alterations in serum PTH and estrone.     

Independent beneficial effects of aged garlic extract intake with regular exercise on cardiovascular risk in postmenopausal women

The purpose of the study was to assess the effects of a 12 weeks aged garlic extract (AGE) regimen with regular exercise on cardiovascular disease (CVD) risk in postmenopausal women. A total of 30 postmenopausal women (54.4 ± 5.4 years) were randomly divided into the following four groups: Placebo (Placebo; n = 6), AGE intake (AGEI; n = 8), exercise and placebo (Ex + Placebo; n = 8), exercise and AGE (Ex + AGE; n = 8) groups. The AGE group consume 80 mg per day, and exercise groups performed moderate exercise (aerobic and resistance) three times per week. After 12 weeks of treatment, body composition, lipid profile, and CVD risk factors were analyzed. Body weight was significantly decreased in AGEI, Ex + Placebo, and Ex + AGE groups compared to baseline. Body fat % was significantly decreased in the AGEI and Ex + Placebo groups. Body mass index (BMI) was significantly decreased in the AGEI, Ex + Placebo, and Ex + AGE groups. Fat-free mass was significantly decreased in the AGEI group. Total cholesterol (TC) was significantly lower in the Ex + Placebo compared to the Placebo group. AGE supplementation or exercise effectively reduced low-density lipoprotein (LDL-C). Triglyceride (TG) was significantly increased in the AGEI group. Malondialdehyde (MDA) levels were significantly decreased in the AGEI, Ex + Placebo, and Ex + AGE compared to the placebo group. AGE supplementation reduced homocysteine levels regardless of whether the women also exercised. The present results suggest that AGE supplementation reduces cardiovascular risk factors independently of exercise in postmenopausal women.     

Dietary flavonoid intake and risk of cardiovascular disease in postmenopausal women.

Flavonoids, a group of phenolic compounds found in fruits and vegetables, are known to have antioxidant properties. They prevent low density lipoprotein oxidation in vitro and thus may play a role in the prevention of coronary heart disease (CHD). In 1986, in a prospective study of 34,492 postmenopausal women in Iowa, the authors examined the association of flavonoid intake with CHD and stroke mortality. Over 10 years of follow-up, 438 deaths from CHD and 131 deaths from stroke were documented. Total flavonoid intake was associated with a decreased risk of CHD death after adjusting for age and energy intake (p for trend = 0.04). This association was attenuated after multivariate adjustment. However, decreased risk was seen in each category of intake compared with the lowest. Relative risks and 95% confidence intervals of CHD death from lowest to highest intake category were 1.0, 0.67 (95% confidence interval (CI) 0.49-0.92), 0.56 (95% CI 0.39-0.79), 0.86 (95% CI 0.63-1.18), and 0.62 (95% CI 0.44-0.87).There was no association between total flavonoid intake and stroke mortality (p for trend = 0.83). Of the foods that contributed the most to flavonoid intake in this cohort, only broccoli was strongly associated with reduced risk of CHD death. The data of this study suggest that flavonoid intake may reduce risk of death from CHD in postmenopausal women.     

The effects of ProAlgaZyme novel algae infusion on metabolic syndrome and markers of cardiovascular health

Background  

Metabolic Syndrome, or Syndrome X, is characterized by a set of metabolic and lipid imbalances that greatly increases the risk of developing diabetes and cardiovascular disease. The syndrome is highly prevalent in the United States and worldwide, and treatments are in high demand. ProAlgaZyme, a novel and proprietary freshwater algae infusion in purified water, has been the subject of several animal studies and has demonstrated low toxicity even with chronic administration at elevated doses. The infusion has been used historically for the treatment of several inflammatory and immune disorders in humans and is considered well-tolerated. Here, the infusion is evaluated for its effects on the cardiovascular risk factors present in metabolic syndrome in a randomized double-blind placebo-controlled study involving 60 overweight and obese persons, ages 25–60. All participants received four daily oral doses (1 fl oz) of ProAlgaZyme (N = 22) or water placebo (N = 30) for a total of 10 weeks, and were encouraged to maintain their normal levels of physical activity. Blood sampling and anthropometric measurements were taken at the beginning of the study period and after 4, 8 and 10 weeks of treatment. Eight participants did not complete the study.     

Changes in body weight, body composition, and energy intake in women fed high- and low-fat diets.

The effects of a 20%-fat diet (LF) on total body weight, lean body weight, and adiposity were studied in 18 premenopausal women with body mass index (BMI) of 18-44. Subjects were fed a 37%-fat (HF) control diet for 4 wk followed by the LF diet for 20 wk. Total body weight, lean body weight, and fat weight were measured at the end of the HF and LF dietary periods by hydrostatic weighing. Despite adjustments in energy intake to maintain weight throughout the study, subjects exhibited a 2.8% decrease in total body weight (P less than 0.0006), an 11.3% decrease in fat weight (P less than 0.0001), and a 2.2% increase in lean body weight (P less than 0.0149) by the end of the LF period. Similar changes were observed in obese (BMI greater than 30) and non-obese women (BMI less than 30). By the end of the LF period, energy intake had increased significantly in comparison with the HF diet (119% of the HF intake, P less than 0.0001). Results could not be explained by changes in daily activity levels and suggest that macronutrient composition plays a role in energy requirements for weight maintenance.     

Preliminary findings on the role of PLIN1 polymorphisms on body composition and energy metabolism response to energy restriction in obese women

The aim of the present study was to investigate the association of PLIN1 11482G>A (rs894160) and PLIN1 13041A>G (rs2304795) polymorphisms with body composition, energy and substrate metabolism, and the metabolic response to a 12-week energy-restricted diet in obese women. The study comprised a total of seventy-eight obese (BMI 34·0 (SD 2·8) kg/m(2)) women (age 36·7 (SD 7) years). We measured weight, height and waist circumference before and after a 12-week controlled energy-restricted diet intervention. Body fat mass and lean mass were measured by dual-energy X-ray absorptiometry. RMR and lipid oxidation rate were measured by indirect calorimetry. We also analysed fasting plasma glucose, insulin, cholesterol and leptin. Women carrying the 11482A allele had a lower reduction in waist circumference than non-A allele carriers (3·2 (SD 0·5) v. 4·6 (SD 0·6) %, respectively, P = 0·047; P for gene-diet interaction = 0·064). Moreover, women with the 11482A allele had a higher decrease in lipid oxidation rate than non-A allele carriers (58·9 (SD 6·7) v. 31·3 (SD 8·2) %, respectively, P = 0·012; P for gene-diet interaction = 0·004). There was no interaction effect between the 13041A>G polymorphism and diet-induced changes on the outcome variables (all P>0·1). These results confirm and extend previous findings suggesting that the PLIN1 11482G>A polymorphism plays a modulating role on diet-induced changes in body fat and energy metabolism in obese women.     

The influence of dietary composition on energy intake and body weight

We review evidence regarding the influence of dietary fat, fiber, the glycemic index and sugar on energy intake and body weight. Although data from comprehensive long-term studies are lacking, published investigations suggest that the previous focus on lowering dietary fat as a means for promoting negative energy balance has led to an underestimation of the potential role of dietary composition in promoting reductions in energy intake and weight loss. More randomized clinical trials are needed to examine the relative utility of different putative dietary factors in the treatment of obesity.