Unprocessed red meat in the dietary treatment of obesity: a randomized controlled trial of beef supplementation during weight maintenance after successful weight loss.
Study Goal
The researchers aimed to compare the effects of moderate-protein and high-protein diets containing different amounts of unprocessed beef on weight maintenance, body composition, and cardiometabolic risk factors after rapid weight loss.
Results Summary
Both diets led to similar outcomes in weight maintenance, fat mass reduction, lean mass increase, and resting energy expenditure, with no significant differences between groups. Cardiometabolic risk factors showed no differential effects between the diets, generally reverting to baseline during maintenance despite mild further weight loss.
Population
108 adults (45 males, 63 females) with BMI 28-40 kg/m², who lost ≥8% body weight during an initial 8-week rapid weight loss phase.
Effective Dosage
25 g beef/day (moderate-protein diet) vs. 150 g beef/day (high-protein diet).
Duration
12-week weight maintenance phase following an 8-week rapid weight loss period.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
moderate-protein diet with 25 g beef/d (B25) | no change | body weight | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #1 |
high-protein diet with 150 g beef/d (B150) | no change | body weight | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #2 |
moderate-protein diet with 25 g beef/d (B25) | no change | fat mass | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #3 |
high-protein diet with 150 g beef/d (B150) | no change | fat mass | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #4 |
moderate-protein diet with 25 g beef/d (B25) | no change | body fat content | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #5 |
high-protein diet with 150 g beef/d (B150) | no change | body fat content | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #6 |
moderate-protein diet with 25 g beef/d (B25) | no change | lean mass | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #7 |
high-protein diet with 150 g beef/d (B150) | no change | lean mass | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #8 |
moderate-protein diet with 25 g beef/d (B25) | no change | resting energy expenditure (REE) | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #9 |
high-protein diet with 150 g beef/d (B150) | no change | resting energy expenditure (REE) | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #10 |
moderate-protein diet with 25 g beef/d (B25) | no change | cardiometabolic risk factors | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #11 |
high-protein diet with 150 g beef/d (B150) | no change | cardiometabolic risk factors | adults with BMI 28-40 kg/m2 who lost ≥8% body weight | null | no differences between groups | #12 |
healthy diets consumed ad libitum that contain a little or a lot of unprocessed beef | no change | body weight | adults with BMI 28-40 kg/m2 after clinically significant rapid weight loss | null | have similar effects | #13 |
healthy diets consumed ad libitum that contain a little or a lot of unprocessed beef | no change | energy metabolism | adults with BMI 28-40 kg/m2 after clinically significant rapid weight loss | null | have similar effects | #14 |
healthy diets consumed ad libitum that contain a little or a lot of unprocessed beef | no change | cardiovascular risk factors | adults with BMI 28-40 kg/m2 after clinically significant rapid weight loss | null | have similar effects | #15 |
BACKGROUND: Consumption of unprocessed red meat in randomized trials has no adverse effects on cardiovascular risk factors and body weight, but its physiological effects during weight loss maintenance are not known. OBJECTIVES: We sought to investigate the effects of healthy diets that include small or large amounts of red meat on the maintenance of lost weight after successful weight loss, and secondarily on body composition (DXA), resting energy expenditure (REE; indirect calorimetry), and cardiometabolic risk factors. METHODS: In this 5-mo parallel randomized intervention trial, 108 adults with BMI 28-40 kg/m2 (45 males/63 females) underwent an 8-wk rapid weight loss period, and those who lost ≥8% body weight (n = 80) continued to ad libitum weight maintenance diets for 12 wk: a moderate-protein diet with 25 g beef/d (B25, n = 45) or a high-protein diet with 150 g beef/d (B150, n = 35). RESULTS: In per protocol analysis (n = 69), mean body weight (-1.2 kg; 95% CI: -2.1, -0.3 kg), mean fat mass (-2.7 kg; 95% CI: -3.4, -2.0 kg), and mean body fat content (-2.6%; 95% CI: -3.1, -2.1%) decreased during the maintenance phase, whereas mean lean mass (1.5 kg; 95% CI: 1.0, 2.0 kg) and mean REE (51 kcal/d; 95% CI: 15, 86 kcal/d) increased, with no differences between groups (all P > 0.05). Results were similar in intention-to-treat analysis with multiple imputation for dropouts (20 from B150 compared with 19 from B25, P = 0.929). Changes in cardiometabolic risk factors were not different between groups, the general pattern being a decrease during weight loss and a return to baseline during weight maintenance (and despite the additional mild reduction in weight and fat mass). CONCLUSIONS: Healthy diets consumed ad libitum that contain a little or a lot of unprocessed beef have similar effects on body weight, energy metabolism, and cardiovascular risk factors during the first 3 mo after clinically significant rapid weight loss.