Key result
Low-carbohydrate diets reduce systolic blood pressure by ~2 mmHg at 12 months versus other diets.
Why the study?
Do low-carbohydrate diets improve weight, BMI, blood pressure, and blood lipids compared to other diets?
Meta-Analysis (n=14,971)
Do low-carbohydrate diets improve weight, BMI, blood pressure, and blood lipids compared to other diets?
Mean Difference: -1.7 (95% CI -3–-0.4)
Low-carbohydrate diets offer short-term weight loss benefits that diminish over time, with small but persistent reductions in blood pressure and minimal effects on lipid profiles.
Background: Low-carbohydrate diets have been used for weight loss and blood glucose control for many years. While advocates claim benefits for weight and blood pressure, concerns have been raised about their effects on lipid profiles (1,2). Clinical trials vary widely in dietary composition, and follow-up times are often short, making the long-term effects on weight control, blood pressure, and lipid profiles unclear. Aim: The primary aim was to assess the effect of low-carbohydrate diets on weight, body mass index (BMI), blood pressure, and blood lipids over time. The secondary aim was to evaluate the influence of carbohydrate levels within the low-carbohydrate diets on the outcomes. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs). PubMed and CENTRAL were searched for RCTs comparing a low-carbohydrate diet to any other diet with a defined carbohydrate level and a follow-up period of ≥12 weeks. Risk of bias was assessed using Cochrane’s Risk of Bias tool 2 (ROB 2). Meta-analyses and meta-regression analyses were performed to assess intervention effects and relevant predictors. Results: A total of 108 trials, including 14,971 participants, were analyzed. The mean age at inclusion was 49 years, 58% of participants were female, and the mean baseline BMI was 33.2 kg/m^2^. The overall risk of bias was moderate to high. Low-carbohydrate diets led to small reductions in weight and BMI, but the effects diminished beyond 12 months. Blood pressure was slightly lower in low-carbohydrate groups at 12 months or longer, with mean differences of -1.7 mmHg (95% CI: -3.0 to -0.4) for systolic and -1.0 mmHg (95% CI: -1.9 to -0.2) for diastolic pressure. There were no significant effects on total cholesterol or LDL cholesterol, but HDL cholesterol was slightly higher, and triglycerides were lower in the low-carbohydrate groups. Results of the meta-analysis are summarized in Table 1. The meta-regression analyses at 3-6 months follow-up showed that lower carbohydrate intake level in the experimental groups was associated with greater reduction in weight and BMI, higher total cholesterol, LDL and HDL, and lower triglycerides. No significant interaction was seen with blood pressure. Conclusions: Low-carbohydrate diets showed short-term benefits for weight loss, but the effects diminished over time. The reduction in blood pressure was small but persisted at longer follow-ups. Effects on lipid profiles were minimal. These findings do not strongly support low-carbohydrate diets for weight loss but suggest no major adverse effects on cardiovascular risk factors. The overall quality of evidence was low, with a moderate to high risk of bias. Meta-regression bubble graphs tri-panel
No takes yet. Share an insight, caveat, or question.
Hagstrom et al. (2025) reported a meta-analysis. Low-carbohydrate diet vs. Any other diet with a defined carbohydrate level was evaluated on systolic blood pressure at 12 months or longer (MD -1.7 mmHg, 95% CI -3.0 to -0.4). Low-carbohydrate diets produced small, transient weight loss and slightly lower systolic blood pressure at ≥12 months (MD -1.7 mmHg; 95% CI -3.0 to -0.4) compared to other diets.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: