Effects of protein intake and gender on body composition changes: a randomized clinical weight loss trial

Abstract

Limited data on sex differences in body composition changes in response to higher protein diets (PRO) compared to higher carbohydrate diets (CARB) suggest that a PRO diet helps preserve lean mass (LM) in women more so than in men.ObjectiveTo compare male and female body composition responses to weight loss diets differing in macronutrient content.DesignTwelve month randomized clinical trial with 4mo of weight loss and 8mo weight maintenance. SubjectsOverweight (N = 130; 58 male (M), 72 female (F); BMI = 32.5 ± 0.5 kg/m2) middle-aged subjects were randomized to energy-restricted (deficit ~500 kcal/d) diets providing protein at 1.6 g.kg-1.d-1 (PRO) or 0.8 g.kg-1.d-1 (CARB). LM and fat mass (FM) were measured using dual X-ray absorptiometry. Body composition outcomes were tested in a repeated measures ANOVA controlling for sex, diet, time and their two- and three-way interactions at 0, 4, 8 and 12mo.ResultsWhen expressed as percent change from baseline, males and females lost similar amounts of weight at 12mo (M:-11.2 ± 7.1 %, F:-9.9 ± 6.0 %), as did diet groups (PRO:-10.7 ± 6.8 %, CARB:-10.1 ± 6.2 %), with no interaction of gender and diet. A similar pattern emerged for fat mass and lean mass, however percent body fat was significantly influenced by both gender (M:-18.0 ± 12.8 %, F:-7.3 ± 8.1 %, p < 0.05) and diet (PRO:-14.3 ± 11.8 %, CARB:-9.3 ± 11.1 %, p < 0.05), with no gender-diet interaction. Compared to women, men carried an extra 7.0 ± 0.9 % of their total body fat in the trunk (P < 0.01) at baseline, and reduced trunk fat during weight loss more than women (M:-3.0 ± 0.5 %, F:-1.8 ± 0.3 %, p < 0.05). Conversely, women carried 7.2 ± 0.9 % more total body fat in the legs, but loss of total body fat in legs was similar in men and women.ConclusionPRO was more effective in reducing percent body fat vs. CARB over 12mo weight loss and maintenance. Men lost percent total body fat and trunk fat more effectively than women. No interactive effects of protein intake and gender are evident.

Should weight loss and maintenance programmes be designed differently for men? A systematic review of long-term randomised controlled trials presenting data for men and women: The ROMEO project

“…Men comprised 36% of participants in 18 of the trials (4771 from a total of 13,305 participants); in four trials numbers of men recruited were unclear [23][24][25][26]. Eleven trials [23,[26][27][28][29][30][31][32][33][34][35] were conducted in the USA; six [24,25,[36][37][38][39] in Finland and one trial from each of the following locations: Canada [40], Israel [41], Scandinavia [42], Sweden [43,43]and the UK [44].…”

“…Three trials [27,35,41] considered different types of reducing diet. Heitzmann [23] considered different types of behaviour change techniques.…”

“…Nine trials recruited participants with concomitant medical conditions: six [23,25,26,33,35,38] recruited participants with type 2 diabetes, two [34,39] recruited participants with impaired glucose tolerance, one recruited participants who were either diagnosed with pre-diabetes mellitus or metabolic syndrome [27] and one [42] recruited participants with hyperlipidaemia. In total, 13,305 men and women were enrolled in the trials.…”

“…Nine trials [27,29,34,[36][37][38]40,43,44] provided data that could be included in the analysis comparing the number of men and women who completed the trials. The total analysis included 3943 participants, with 1255 men (31.8%) and 2688 women (68.2%) ( Tables 1 and 2).…”

“…For the analysis comparing mean weight loss between men and women, a total of 13 studies had eligible data [24][25][26][27]29,[31][32][33][34][36][37][38]40]. There were a total of 5890 participants with 2213 (37.6%) men and 3677 (62.4%) women (Figures 1-2).…”