Join Date: Oct 2009
Location: Buffalo, NY
A randomized trial of a hypocaloric high-protein diet, with and without exercise, on weight loss, fitness, and markers of the Metabolic Syndrome in overweight and obese women
Author(s): Meckling KA, Sherfey R
Source: APPLIED PHYSIOLOGY NUTRITION AND METABOLISM-PHYSIOLOGIE APPLIQUEE NUTRITION ET METABOLISME Volume: 32 Issue: 4 Pages: 743-752 Published: AUG 2007
The purpose of this study was to examine the effects of 3:1 and 1: 1 carbohydrate to protein ratios, hypocaloric diets with and without exercise, and risk factors associated with the Metabolic Syndrome in overweight and obese Canadian women. Groups were designated as control diet (CON), control diet with exercise (CONEx), high-protein (HP), or high-protein with exercise (HPEx). Free-living women from the Guelph community were studied in a university health and fitness facility. The participants were 44 of 60 overweight and obese women who had been randomized to the 4 weight-loss programs. Habitual diets of the subjects were energy restricted and were to contain either a 1: 1 or 3:1 ratio of carbohydrate to protein energy. Subjects either exercised 3 times/week or maintained their normal level of activity for 12 weeks. The main outcome measures were weight loss, blood lipids, blood pressure, insulin, body composition, nitrogen balance, fitness, and resting energy expenditure. All groups lost weight over the 12 week period: -2.1 kg for the CON group, -4.0 kg in the CONEx group, -4.6 kg in the HP group, and -7.0 kg in the HPEx. All participants exhibited improved body composition, decreased blood pressure, and decreased waist and hip circumference. Actual diets consumed by the subjects contained ratios of carbohydrate to protein of 3.0:1, 2.7:1, 1.5: 1, and 0.96:1 for the CON, CONEx, HP, and HPEx groups, respectively. Cardiovascular fitness improved in both exercise groups. There were no changes in resting energy expenditure. No adverse events were reported. Significant changes in blood lipids included decreased total cholesterol in the HP and CONEx groups, decreased low-density lipoprotein cholesterol in the HP group only, and decreased blood triglycerides in the HPEx group only. High-density lipoprotein cholesterol, fasting blood glucose, and fasting insulin levels were unaltered by diet or exercise. A high-protein diet was superior to a low-fat, high-carbohydrate diet either alone or when combined with an aerobic/resistance-training program in promoting weight loss and nitrogen balance, while similarly improving body composition and risk factors for the Metabolic Syndrome in overweight and obese Canadian women.
High protein diets decrease total and abdominal fat and improve CVD risk profile in overweight and obese men and women with elevated triacylglycerol
Author(s): Clifton PM, Bastiaans K, Keogh JB
Source: NUTRITION METABOLISM AND CARDIOVASCULAR DISEASES Volume: 19 Issue: 8 Pages: 548-554 Published: OCT 2009
Background and aims: It is unclear whether high protein weight loss diets have beneficial effects on weight Loss, abdominal fat mass, lipids, glucose and insulin compared to conventional low fat diets in subjects at increased risk of cardiovascular disease (CVD) because of elevated glucose and triglyceride concentrations. Our objective was to determine the effects of high protein (HP) compared to standard protein (SP) diets on CVD risk in obese adults.
Methods and results: Data from three, 12 week, randomized parallel trials with subjects assigned to either HP or SP diet (5500-6500 kJ/day) were pooled. Weight, body composition (dual energy X-ray absorptiometry), lipids, insulin and glucose were measured before and after weight loss. Data from 215 subjects (49.9 +/- 9.8 years, BMI 33.5 +/- 3.7 kg/m2), 108 HP, 107 SP were analyzed. Weight loss (HP diet 7.82 +/- 0.37 kg; SP diet 7.65 +/- 0.39 kg, NS) and total fat toss were not different (HP 6.8 +/- 4.3 kg; LP 6.4 +/- 4.7 kg, NS on intention to treat analysis). The reduction in triacylglycerol. (TAG) was greater on HP than SP 0.48 +/- 0.07 mmol/L vs 0.27 +/- 0.06 mmol/L, (P < 0.001). Subjects with TAG greater than the median (>1.54 mmol/L. at baseline) lost more weight (HP 8.5 +/- 0.6; SP 6.9 +/- 0.6 kg, P = 0.01, diet by TG group), total (HP 6.17 +/- 0.50 kg; SP 4.52 +/- 0.52 kg, P = 0.007) and abdominal fat (HP 1.92 +/- 0.17 kg; SP 1.23 +/- 0.19 kg, P = 0.005) on HP. Total cholesterol (12 vs 6%, HP vs; SP) and TAG (39 vs 20%, HP vs SP) decreased to a greater extent in these subjects (both P <= 0.05) on HP.
Conclusion: Short-term high protein weight loss diets had beneficial. effects on total cholesterol and triacylglycerol in overweight and obese subjects and achieved greater weight Loss and better lipid results in subjects at increased risk of CVD. These observations provide further information regarding the utility of this dietary approach in effectively managing body weight and composition and reducing CVD risk in overweight and obese individuals. (C) 2008 Elsevier B.V. All rights reserved.
The effect of a low-fat, high-protein or high-carbohydrate ad libitum diet on weight loss maintenance and metabolic risk factors
Author(s): Claessens M, van Baak MA, Monsheimer S, et al.
Source: INTERNATIONAL JOURNAL OF OBESITY Volume: 33 Issue: 3 Pages: 296-304 Published: MAR 2009
Abstract: Background: High-protein (HP) diets are often advocated for weight reduction and weight loss maintenance. Objective: The aim was to compare the effect of low-fat, high-carbohydrate (HC) and low-fat, HP ad libitum diets on weight maintenance after weight loss induced by a very low-calorie diet, and on metabolic and cardiovascular risk factors in healthy obese subjects.
Design: Forty-eight subjects completed the study that consisted of an energy restriction period of 5-6 weeks followed by a weight maintenance period of 12 weeks. During weight maintenance subjects received maltodextrin (HC group) or protein (HP group) (casein (HPC subgroup) or whey (HPW subgroup)) supplements (2 x 25 g per day), respectively and consumed a low-fat diet.
Results: Subjects in the HP diet group showed significantly better weight maintenance after weight loss (2.3 kg difference, P = 0.04) and fat mass reduction (2.2 kg difference, P = 0.02) than subjects in the HC group. Triglyceride (0.6 mM difference, P = 0.01) and glucagon (9.6 pg ml(-1) difference, P = 0.02) concentrations increased more in the HC diet group, while glucose (0.3 mM difference, P = 0.02) concentration increased more in the HP diet group. Changes in total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, insulin, HOMAir index, HbA1c, leptin and adiponectin concentrations did not differ between the diets. No differences were found between the casein-or whey-supplemented HP groups.
Conclusions: These results show that low-fat, high-casein or whey protein weight maintenance diets are more effective for weight control than low-fat, HC diets and do not adversely affect metabolic and cardiovascular risk factors in weight-reduced moderately obese subjects without metabolic or cardiovascular complications.
I can go on and on, just do a pubmed search. Good stuff.