Effects of a higher vs. lower protein diet on weight loss in teenagers: Results from a randomized controlled trial

Abstract

ObjectiveTo provide pilot data on weight loss efficacy in overweight and obese adolescents during isocaloric lower vs higher protein weight loss diets utilizing the U.S. Department of Agriculture (USDA) MyPlate nutrition guide.MethodsThirty two, 12–17 year old adolescents with body mass index ≥ 85th percentile were recruited for a 12‐week free‐living weight loss intervention. Participants were randomized to either a lower protein group with 15% of energy as protein and 60% of energy from carbohydrate or a higher protein group with 30% of energy as protein and 45% of energy from carbohydrate. Both diets restricted energy intake by 25%. Dietary counseling was based on the USDA MyPlate guidelines. The first intervention session was individual followed by 6 (biweekly) group sessions. Participants had anthropometric measurements and performed retrospective visual analogue scale (VAS) appetite ratings at baseline and week 12.ResultsParticipants were 75 % female and 62.5 % black. The baseline mean (± SD) age, body weight, and BMI z‐score were 14.3 ± 1.5 y, 96.0 ± 21.9 kg, and 2.21 ± 0.48, respectively. The lower protein group reduced BMI z‐score compared to the higher protein group (0.18 ± 0.16 vs. 0.05 ± 0.09; p<0.05). No other group differences were found but fullness tended to increase in the higher protein group (0.5 ± 20.5 vs. 14.9 ± 15.2; p=0.08). Participants lost 3.1 ± 2.0 kg vs. 1.5 ± 4.2 kg body weight and 2.8 ± 2.4 % vs. 3.0 ± 5.2 % body fat in the lower vs. higher protein groups, respectively. The lower protein group change from baseline BMI z‐score, body weight, and body fat were reduced (p≤0.002) but the higher protein group change from baseline values were not different from baseline. Exploratory analyses, with the protein groups combined, indicated that overweight adolescents reduced BMI z‐score 0.38 ± 0.12 compared to 0.07 ± 0.08 in the obese subgroup (p<0.01).ConclusionsParticipants in the higher protein group tended to increase fullness, but this did not translate to greater weight loss. Higher dietary protein intake should not be recommended for weight loss in group based interventions in this study population. An adolescent intervention based on the USDA MyPlate guidelines is efficacious for weight loss in adolescents.Support or Funding InformationNIH U54 GM104940 and NIH P30 DK072476