Effect of Carbohydrate-Restricted Dietary Patterns Based on Prescribed and Self-Reported Intake in Adults with...

Carbohydrate (CHO) restriction has regained attention as a dietary approach for weight management and cardiometabolic health, though evidence supporting its effectiveness remains controversial, particularly regarding degree of restriction.

Examine effects of CHO-restricted versus higher CHO dietary approaches on weight- and cardiometabolic-related outcomes in adults with overweight or obesity without other established disease.

Searches of MEDLINE, CINAHL, and Cochrane databases identified relevant randomized controlled trials (RCTs) published from 2010-2025. Primary outcomes were anthropometric outcomes (body weight, BMI, waist circumference, fat and lean body mass) and glycemic outcomes (fasting blood glucose, HbA1c). Meta-analyses were conducted using random-effects models for an outcome of interest. Heterogeneity was assessed using I², evidence certainty using the GRADE methodology, and publication bias was assessed using Begg and Egger's statistic and by generating funnel plots.

Twenty-three RCTs, represented in 28 articles, were included. Degree of CHO restriction varied across studies, with self-reported intake often less restrictive than prescribed levels. CHO restriction resulted in modest but significant reductions in body weight (Mean difference (MD): -1.32kg, 95% CI: -2.03, -0.61), waist circumference (MD: -0.89 cm, 95% CI: -1.44, -0.34), and fat mass (standardized mean difference (SMD): -0.29, 95% CI: -0.48, -0.10) compared to higher CHO diets. CHO restriction reduced fasting blood glucose (MD: -0.08mmol/L, 95% CI: -0.17, 0.00), HbA1c (MD: -0.16%, 95% CI: -0.28, -0.04), triglycerides (MD: -0.17mmol/L, 95% CI: -0.26, -0.08), and systolic blood pressure (MD: -4.86mmHg, 95% CI: -6.60, -3.11).

CHO restriction (<45% total daily energy intake) likely provides modest benefits for weight management and certain cardiometabolic risk factors in adults with overweight or obesity.