Is protein the forgotten ingredient: Effects of higher compared to lower protein diets on cardiometabolic risk factors. A systematic review and meta-analysis of randomised controlled trials

Research output: Contribution to journalReviewResearchpeer-review

  • Yakima D Vogtschmidt
  • Raben, Anne
  • Faber, Ilona
  • Claudia de Wilde
  • Julie A Lovegrove
  • D Ian Givens
  • Andreas F H Pfeiffer
  • Sabita S Soedamah-Muthu

Background and aims: Higher protein (HP) diets may lead to lower cardiometabolic risk, compared to lower protein (LP) diets. This systematic review and meta-analysis aims to investigate the effects of HP versus LP diets on cardiometabolic risk factors in adults, using the totality of the current evidence from randomised controlled trials (RCTs).

Methods: Systematic searches were conducted in electronic databases, up to November 2020. Random effects meta-analyses were conducted to pool the standardised mean differences (SMD) and 95% confidence intervals (CI). The main outcomes were weight loss, body mass index (BMI), waist circumference, fat mass, systolic and diastolic BP, total cholesterol, HDL-and LDL-cholesterol, triacylglycerol, fasting glucose and insulin, and glycated haemoglobin.

Results: Fifty-seven articles reporting on 54 RCTs were included, involving 4344 participants (65% female, mean age: 46 (SD 10) years, mean BMI: 33 (SD 3) kg/m2), with a mean study duration of 18 weeks (range: 4 to 156 weeks). Compared to LP diets (range protein (E%):10-23%), HP diets (range protein (E%): 20-45%) led to more weight loss (SMD -0.13, 95% CI: -0.23, -0.03), greater reductions in fat mass (SMD -0.14, 95% CI: -0.24, -0.04), systolic BP (SMD -0.12, 95% CI: -0.21, -0.02), total cholesterol (SMD -0.11, 95% CI: -0.19, -0.02), triacylglycerol (SMD -0.22, 95% CI: -0.30, -0.14) and insulin (SMD -0.12, 95% CI: -0.22, -0.03). No significant differences were observed for the other outcomes.

Conclusions: Higher protein diets showed small, but favourable effects on weight loss, fat mass loss, systolic blood pressure, some lipid outcomes and insulin, compared to lower protein diets.

Original languageEnglish
Pages (from-to)124-135
Number of pages12
Publication statusPublished - 2021

Bibliographical note

Copyright © 2021 Elsevier B.V. All rights reserved.

    Research areas

  • Faculty of Science - Cardiometabolic, Meta-analysis, Protein diet, Randomised controlled trial, Systematic review

ID: 272166244