The effect of ethanol on fat storage in healthy subjects.
Level 3 - non-randomized controlled study
Controlled within-subject crossover study with non-randomized or unspecified session sequence.
PubMed 1545851 · doi:10.1056/NEJM199204093261503
What was done
Eight healthy men underwent two 48-hour sessions inside an indirect-calorimetry chamber to measure 24-hour substrate oxidation and energy expenditure. In each session, the first 24 hours served as an unsupplemented control period. On the second day, ethanol was administered at 25% of total daily energy requirement (mean ± SD: 96 ± 4 g/day) as either an addition to the normal diet or as an isocaloric substitution for dietary carbohydrates and lipids.
What was found
Both ethanol regimens significantly reduced 24-hour lipid oxidation compared to baseline control days: - Ethanol addition reduced lipid oxidation by 49.4 ± 6.7 g/day (a 36 ± 3% reduction, P < 0.001). - Ethanol substitution reduced lipid oxidation by 44.1 ± 9.3 g/day (a 31 ± 7% reduction, P < 0.0025). This inhibition occurred exclusively during daytime hours (8:30 a.m. to 11:30 p.m.) when ethanol was consumed and metabolized. Neither regimen significantly altered carbohydrate or protein oxidation. Total 24-hour energy expenditure increased by 7 ± 1% with ethanol addition (P < 0.001) and by 4 ± 1% with ethanol substitution (P < 0.025).
Why it matters
The study demonstrates that ethanol acutely suppresses whole-body fat oxidation by over 30% regardless of whether it is added or substituted into the diet, creating conditions that favor fat storage.
Limits
The sample size was very small (n = 8) and restricted to healthy men over acute 24-hour intervention windows. The abstract does not state whether session order was randomized, nor did it measure long-term fat mass accumulation, chronic adaptations, or effects in women.
Cited by
- supports Ingesting alcohol increases human whole-body energy expenditure during metabolic chamber testing.