Background: Little is known about the relative efficacy of high-protein vs. conventional diet plans that include partial meal replacements on body fat loss in obese subjects with metabolic syndrome.
Objective: We aimed to evaluate the efficacy of two low-calorie diets with partial meal replacement plans–a high-protein plan (HP) and a nutritionally balanced conventional (C) plan–on reducing obesity in obese subjects with metabolic syndrome.
Design: In a 12-week, double-blind study, we randomised 75 participants to either the HP- or the C-plan group. We recorded key metrics at 0 and 12 weeks.
Results: The overall mean weight loss was 5 kg in the HP-plan group and 4.9 kg in the C-plan group (p = 0.72). Truncal fat mass decreased 1.6 kg in the HP-plan group (p < 0.05) and 1.5 kg in the C-plan group (p < 0.05), while whole body fat mass decreased 2.5 kg in the HP-plan group (p < 0.05) and 2.3 kg in the C-plan group (p < 0.05). Between-group losses did not differ significantly for truncal (p = 0.52) or whole body (p = 0.77) fat mass. Among subjects with ≥ 70% dietary compliance, however, truncal and whole body fat mass decreased more in the HP-plan group (Δ2.2 kg and Δ3.5 kg respectively) than in the C-plan group (Δ1.5 kg and Δ1.9 kg respectively) (p < 0.05).
Conclusion: The HP- and C-plans had a similar effect on weight and abdominal fat reduction, but the HP-plan was more effective in reducing body fat among compliant subjects.