Diet induced thermogenesis measured over 24h in a respiration chamber: effect of diet composition.
Level 2 - randomized trial
Randomized crossover trial in humans
PubMed 10193874 · doi:10.1038/sj.ijo.0800810
What was done
Eight healthy female volunteers (mean age 27 ± 3 years, BMI 23 ± 3 kg/m²) spent two separate 36-hour periods in a respiration chamber in random order. They consumed two isoenergetic, isovolumetric diets matched for taste, smell, and appearance: a high protein and carbohydrate (HP/C) diet (60% carbohydrate, 10% fat, 30% protein) and a high-fat (HF) diet (30% carbohydrate, 60% fat, 10% protein). Diet-induced thermogenesis (DIT), sleeping metabolic rate, activity-induced energy expenditure, and 24-hour energy expenditure were measured.
What was found
DIT was higher in all subjects on the HP/C diet compared to the HF diet (1295 kJ/d vs 931 kJ/d; 14.6% vs 10.5% of energy intake; P < 0.02). There was no statistically significant difference in sleeping metabolic rate, activity-induced energy expenditure, or total 24-hour energy expenditure between the two diets, though a trend toward higher energy expenditure was noted on the HP/C diet.
Why it matters
This study provides direct whole-room calorimetry evidence that shifting macronutrient composition toward protein and carbohydrate increases 24-hour diet-induced thermogenesis compared to a high-fat diet.
Limits
The sample size was very small (n = 8) and included only healthy young women, limiting generalizability to males, older adults, or individuals with obesity. In addition, the short observation window (36 hours per condition) cannot determine whether differences persist with long-term metabolic adaptation.
Cited by
- supports Consuming a higher protein diet increases the thermic effect of food, causing an increase in caloric expenditure required for digestion.