Comparing effectiveness of fat burners and thermogenic supplements to diet and exercise for weight loss and cardiometabolic health: Systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of clinical intervention studies
PubMed 33427571 · doi:10.1177/0260106020982362
What was done
A PRISMA-guided systematic review and meta-analysis searched Medline, PubChem, PubMed, CINAHL, SPORTDiscus, and Google Scholar through January 2019. It included 21 studies lasting more than 8 weeks in participants with a BMI over 24.9 kg/m² evaluating fat-burner and thermogenic dietary supplements. Pooled effect sizes and 95% confidence intervals were evaluated for body mass, fat mass, fat-free mass, total cholesterol, HDL, LDL, and resting metabolic rate. Intra-study effect sizes were compared against historical benchmarks for exercise or diet plus exercise using 2x2 chi-square analysis.
What was found
The abstract reports a general trend toward beneficial point estimates (effect size > 0.00), but the 95% confidence intervals crossed 0.00 across pooled outcomes, indicating no statistically significant benefit for body mass, body composition, or cardiometabolic markers. Chi-square analysis indicated that responses from weight-loss supplements were significantly less effective than standard exercise or diet plus exercise regimens alone. Specific point estimates and exact confidence intervals were not reported in the abstract.
Why it matters
These findings counter widespread commercial claims by showing that over-the-counter thermogenic supplements provide negligible long-term clinical utility for weight loss and cardiometabolic health compared to lifestyle modification.
Limits
The abstract omits exact numerical effect sizes, confidence intervals, participant headcounts, and adverse event data. Comparing supplements to diet and exercise relied partly on indirect comparisons against historical reference values rather than direct multi-arm randomized trials. The review pooled heterogeneous supplement formulations under broad categories.
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