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United States Department of Agriculture

Agricultural Research Service

Research Project: MICRONUTRIENT ROLES IN PHYSIOLOGY AND HEALTH Title: Varying protein source and quantity does not significantly improve weight loss, fat loss, or satiety in reduced energy diets among midlife adults

Authors
item Aldrich, Noel -
item Reicks, Marla -
item Sibley, Shalamar -
item Redmon, J -
item Thomas, William -
item Raatz, Susan

Submitted to: Nutrition Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 21, 2011
Publication Date: February 1, 2011
Repository URL: http://handle.nal.usda.gov/10113/58141
Citation: Aldrich, N.D., Reicks, M.M., Sibley, S.D., Redmon, J.B., Thomas, W., Raatz, S.K. 2011. Varying protein source and quantity does not significantly improve weight loss, fat loss, or satiety in reduced energy diets among midlife adults. Nutrition Research. 31(2):104-112.

Interpretive Summary: This pilot study tested whether protein source and quantity in a low calorie diet would result in weight loss, body composition changes, and renin angiotensin aldosterone system (RAAS) activity modification in midlife adults. Eighteen subjects enrolled in a 5 month weight reduction study, involving 8 weeks controlled food intake followed by 12 weeks ad libitum intake. Subjects were randomized to one of three treatment groups: control diet (CD) (55% carbohydrate: 15% protein: 30% fat), mixed protein (MP) (40% carbohydrate: 30% protein: 30% fat), or whey protein (WP) (40% carbohydrate: 15% mixed protein: 15% whey protein: 30% fat). Weight, metabolic measures, body composition by dual energy x-ray absorptiometry (DXA), and resting energy expenditure were measured at baseline, 8, and 20 weeks. Fifteen of 18 subjects completed the study and all subjects lost weight. No statistically significant differences in total weight loss or total fat loss were observed between treatments, however, a trend toward greater total weight loss (p = 0.08) and total fat loss (p=0.09) was observed in the WP group compared to the CD group. No RAAS changes were observed, but a decrease in systolic blood pressure at the end of the study was significantly greater (p <0.05) in the WP group compared to the CD group. Increased protein intake and varied sources of protein did not result in statistically significant differences in reduced energy diet comparisons.

Technical Abstract: This pilot study tested whether varying protein source and quantity in a reduced energy diet would result in significant differences in weight, body composition, and renin angiotensin aldosterone system activity in midlife adults. Eighteen subjects enrolled in a 5 month weight reduction study, involving 8 weeks controlled food intake followed by 12 weeks ad libitum intake. Subjects were randomized to one of three treatment groups: control diet (CD) (55% carbohydrate: 15% protein: 30% fat), mixed protein (MP) (40% carbohydrate: 30% protein: 30% fat), or whey protein (WP) (40% carbohydrate: 15% mixed protein: 15% whey protein: 30% fat). Weight, metabolic measures, body composition by dual energy x-ray absorptiometry (DXA), and resting energy expenditure were measured at baseline, 8, and 20 weeks. Fifteen of 18 subjects completed the study and all subjects lost weight. No statistically significant differences in total weight loss or total fat loss were observed between treatments, however, a trend toward greater total weight loss (p = 0.08) and total fat loss (p=0.09) was observed in the WP group compared to the CD group. Fat loss in the leg and gynoid regions was greater (p < 0.05) in the WP group than the CD group. No RAAS mediated response was observed, but a decrease in systolic blood pressure at the end of the study was significantly greater (p <0.05) in the WP group compared to the CD group. Increased protein intake and varied sources of protein did not result in statistically significant differences in reduced energy diet comparisons.

Last Modified: 11/24/2014
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