Low-carbohydrate diets showed no significant difference versus low-fat diets for inflammatory markers in adults over 5.5 months

Chronic low-grade inflammation is implicated in obesity and related diseases. Dietary composition may modulate inflammatory responses, but the comparative effects of low-carbohydrate (LC) and low-fat (LF) diets remain unclear. We conducted a systematic review and meta-analysis of randomized clinical trials assessing the impact of LC vs LF diets on concentrations of interleukin-6, C-reactive protein, tumor necrosis factor-alpha, adiponectin, leptin, and resistin in adults, to test the hypothesis that LC diets exert beneficial effects on these biomarkers when compared to LF diets. Literature searches were conducted in four databases through June 2025. Two independent reviewers screened and extracted data. Meta-analyses using random-effects models were performed; outcomes were reported as standardized mean differences (SMD) with 95% confidence intervals (CI). Twenty-five studies (n = 2222 participants) met eligibility criteria. Median intervention duration was 24 weeks (range: 8-144). On average, carbohydrate intake accounted for 25.8% of total daily energy intake in LC diets and 54% in LF diets, whereas fat intake averaged 48.6% and 26% of total daily energy intake, respectively. No significant differences were found between LC and LF diets for interleukin-6 (SMD: -0.01; 95% CI: -0.12 to 0.09), C-reactive protein (SMD: -0.01; 95% CI: -0.11 to 0.09), or tumor necrosis factor-alpha (SMD: -0.03; 95% CI: -0.18 to 0.11), nor for adiponectin, leptin, or resistin. Risk of bias was low in most studies. Our results suggest that LC diets were not superior to LF diets in modulating the inflammatory and adipokine profiles in adults. Future trials should explore the influence of nutrient quality, adherence, and metabolic status.