Appetite control and biomarkers of satiety with vegetarian (soy) and meat-based high-protein diets for weight loss in obese men: a randomized crossover trial

Am J Clin Nutr. 2014 Aug;100(2):548-58. doi: 10.3945/ajcn.113.077503. Epub 2014 Jun 18.

Abstract

Background: There is limited evidence with regard to the effect of different sources of protein on appetite during weight loss. Vegetarian and meat-based high-protein diets may have contrasting effects on appetite and biomarkers of protein-induced satiety.

Objective: The aim was to assess appetite response to meat or vegetarian high-protein weight-loss (HPWL) diets in obese men to monitor plasma amino acid profile and gut peptide response as potential satiety biomarkers.

Design: Twenty obese [body mass index (in kg/m²): 34.8] men participated in a dietary intervention study. After 3 d of a maintenance diet, they were provided in a crossover design with either a vegetarian HPWL (Soy-HPWL) or a meat-based HPWL (Meat-HPWL) diet for 2 wk. Both diets comprised 30% protein, 30% fat, and 40% carbohydrate, provided to measured resting metabolic rate. Body weight and the motivation to eat were measured daily. Plasma satiety biomarkers were collected during a test-meal challenge (5 h) at the end of each diet period.

Results: Over the 2 wk, subjects lost, on average, 2.41 and 2.27 kg with consumption of the Soy- and Meat-HPWL diets, respectively [P = 0.352; SE of the difference (SED): 0.1]. ANOVA confirmed that subjectively rated hunger (P = 0.569; SED: 3.8), fullness (P = 0.404; SED: 4.1), desire to eat (P = 0.356; SED: 3.7), preservation of lean body mass (P = 0.334; SED: 0.2), and loss of percentage fat mass (P = 0.179; SED: 0.2) did not differ between the 2 HPWL diets. There were differences in absolute concentrations of ghrelin and peptide YY between the 2 HPWL diets, although the response as net area under the curve was not different.

Conclusions: Appetite control and weight loss were similar for both HPWL diets. Gut hormone profile was similar between the diets, which suggests that vegetarian diets can be as effective as meat-based diets for appetite control during weight loss.

Trial registration: ClinicalTrials.gov NCT02080325.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Amino Acids / blood
  • Appetite Regulation*
  • Biomarkers / blood
  • Body Mass Index
  • Cross-Over Studies
  • Diet, Reducing*
  • Diet, Vegetarian*
  • Dietary Proteins / administration & dosage*
  • Dietary Proteins / metabolism
  • Food Preferences
  • Ghrelin / blood
  • Humans
  • Male
  • Meat
  • Middle Aged
  • Obesity / blood
  • Obesity / diet therapy*
  • Obesity / metabolism
  • Peptide YY / blood
  • Plant Proteins, Dietary / administration & dosage*
  • Plant Proteins, Dietary / metabolism
  • Satiety Response
  • Scotland
  • Soybean Proteins / administration & dosage*
  • Soybean Proteins / metabolism
  • Weight Loss

Substances

  • Amino Acids
  • Biomarkers
  • Dietary Proteins
  • GHRL protein, human
  • Ghrelin
  • Plant Proteins, Dietary
  • Soybean Proteins
  • Peptide YY

Associated data

  • ClinicalTrials.gov/NCT02080325