Effects of Varying Protein Amounts and Types on Diet-Induced Thermogenesis: A Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of 52 intervention studies
PubMed 39486625 · doi:10.1016/j.advnut.2024.100332
What was done
A systematic review and meta-analysis evaluated 52 studies identified from 3,894 database records through June 2024. The authors examined the effects of isocaloric meals or diets varying in protein quantity or source on diet-induced thermogenesis (DIT), total daily energy expenditure (TDEE), and resting energy expenditure (REE). Pooled standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated across acute single-meal studies and chronic dietary interventions lasting from 4 days to 1 year.
What was found
In acute studies, higher-protein meals significantly elevated DIT (SMD: 0.45; 95% CI: 0.26, 0.65; P < 0.001) and TDEE (SMD: 0.52; 95% CI: 0.30, 0.73; P < 0.001). Subgroup analysis demonstrated significant DIT increases in normal-weight participants but not in individuals with overweight or obesity. In chronic studies, higher-protein diets led to small-to-moderate increases in TDEE (SMD: 0.29; 95% CI: 0.10, 0.48; P = 0.039) and REE (SMD: 0.18; 95% CI: 0.01, 0.35; P = 0.039), but showed no significant effect on DIT (SMD: 0.10; 95% CI: -0.08, 0.28; P = 0.27). Protein type had no detectable impact on any energy metabolism metric.
Why it matters
This review establishes that while higher protein intake modestly increases daily energy expenditure across acute and chronic timelines, the choice of protein source appears irrelevant to energy metabolism.
Limits
The total participant count and exact macronutrient compositions are not reported in the abstract. Chronic diets did not show a statistically significant effect on isolated DIT despite changes in TDEE. Additionally, whether the lack of acute DIT response in participants with overweight/obesity stems from biological differences or study design variation remains undetermined.
Cited by
- supports Consuming a higher protein diet increases the thermic effect of food, causing an increase in caloric expenditure required for digestion.