Research

Hormonal

Long-term high-protein diets significantly improve fasting insulin levels compared to low-protein diets, but this benefit disappears when only high-quality studies are analyzed.

You may see a small reduction in fasting insulin with a high-protein diet, but this does not guarantee better weight loss or health outcomes. Do not rely on high protein solely for insulin management, as the effect is inconsistent and not clinically significant in high-quality studies.

ModerateQualifiesMEDIUM confidence
improvements of fasting insulin was significantly more pronounced following high protein diets as compared to the low protein counterparts (weighted mean difference: -0.71 μIU/ml, 95% CI −1.36 to −0.05, p = 0.03).
Lukas Schwingshackl et al. · Nutrition Journal · 2013

Why this rating

Statistically significant in primary analysis but lost in sensitivity analysis of high-quality RCTs.

Source

Long-term effects of low-fat diets either low or high in protein on cardiovascular and metabolic risk factors: a systematic review and meta-analysis

Lukas Schwingshackl et al. · Nutrition Journal · 2013

DOI 10.1186/1475-2891-12-48

Meta-analysis · 15 studiesCited 180×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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