Impact of the ketogenic diet as a dietary approach on cardiovascular disease risk factors: a meta-analysis of randomized clinical trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 39097343 · doi:10.1016/j.ajcnut.2024.04.021
What was done
Authors conducted a systematic review and meta-analysis (PROSPERO CRD42023491853) searching PubMed, Web of Science, EMBASE, and Cochrane Library for randomized controlled trials comparing ketogenic diets with control diets. Fixed- and random-effects models were used to calculate mean differences (MD) and 95% confidence intervals (CIs) for changes in cardiovascular disease risk factors.
What was found
Across 27 RCTs (n = 1,278), ketogenic diets significantly increased: - Total cholesterol: MD 0.36 mmol/L (95% CI: 0.15 to 0.57; I² = 85.1%) - LDL cholesterol: MD 0.35 mmol/L (95% CI: 0.20 to 0.50; I² = 73.9%) - HDL cholesterol: MD 0.16 mmol/L (95% CI: 0.09 to 0.23; I² = 86.7%) Ketogenic diets significantly decreased: - Triglycerides: MD -0.20 mmol/L (95% CI: -0.29 to -0.11; I² = 72.2%) - Blood glucose: MD -0.18 mmol/L (95% CI: -0.33 to -0.02; I² = 76.4%) - Blood insulin: MD -8.32 pmol/L (95% CI: -14.52 to -2.12; I² = 81.5%) - Diastolic blood pressure: MD -1.41 mmHg (95% CI: -2.57 to -0.26; I² = 49.1%) - Body weight: MD -2.59 kg (95% CI: -3.90 to -1.28; I² = 87.4%) - Body mass index: MD -1.59 kg/m² (95% CI: -2.32 to -0.86; I² = 84.5%)
Why it matters
This meta-analysis highlights the conflicting cardiovascular risk profile of ketogenic diets: while they improve glycemic markers, weight, and triglycerides, they simultaneously elevate circulating atherogenic lipoproteins (total and LDL cholesterol).
Limits
High statistical heterogeneity (I² > 70% for most outcomes) was present throughout the meta-analysis. The abstract does not specify intervention durations, the dietary composition of the control groups, baseline health status of participants, or hard cardiovascular endpoints (e.g., major adverse cardiovascular events or mortality).
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