Highlights
- •Dietary proteins are an important part of a healthy diet.
- •Higher protein diets showed favourable effects on cardiometabolic risk factors.
- •The effects were small and more research on the long-term impacts is needed.
Abstract
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.
Graphical abstract
Graphical Abstract
Keywords
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Article Info
Publication History
Published online: May 25, 2021
Accepted:
May 19,
2021
Received in revised form:
April 25,
2021
Received:
March 4,
2021
Identification
Copyright
© 2021 Elsevier B.V. All rights reserved.
