Efficacy of low‐calorie, partial meal replacement diet plans on weight and abdominal fat in obese subjects with metabolic syndrome: a double‐blind, randomised controlled trial of two diet plans – one high in protein and one nutritionally balanced

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.