Effectiveness of Low Carbohydrate diets for long-term weight loss in obese individuals: a meta-analysis of randomized controlled trials

Aim: To assess whether low-carbohydrate (LC) diets are associated with differences in weight loss and well-being in people with obesity, and to assess their cardiovascular and renal safety. Methods: Meta-analysis of Randomized Controlled Trials longer than 3 months, retrieved through an extensive search on MedLine and Embase online databases, comparing weight loss with LC diets and control diets in people with BMI >30 kg/m2 . Results: We retrieved 25 trials. LC diets were associated with significant reduction of body weight at 3-4 (MD -2.59 [-3.93, -1.25] kg), and at 6-8 months (MD -2.64 [-4.32, -0.95]), no diffeence at 10-14 and 18-30 months, vs controls. Compared with controls, LC diets were associated with significantly greater BMI reduction at 3-4 months (-1.66 [-2.70, -0.61] kg/m2) , but not at other timepoints. Since only four trials reported data on renal function and psychological parameters, renal safety and impact on well-being could not be assessed. Differences in fasting plasma glucose at any time point were not statistically significant. No significant difference in total or LDL Cholesterol or blood pressure were found in the long-term, whereas a long-term reduction of triglycerides (23.26 [-45.53, -0.98] mg/dl, at 18-30 months), and increase of HDL cholesterol, MD 4.94 [0.30, 9.57] mg/dl at 18-30 months), was observed. Conclusion: LC diets are associated with greater short-term weight loss than non-carbohydrate-restricted diets and a longer-term favorable effect on cardiovascular risk factors. Further evidence on long-term efficacy and renal safety is needed before LC diets can be recommended as the preferred diets in obese persons. This article is protected by copyright. All rights reserved.