Covert manipulation of the ratio of dietary fat to carbohydrate and energy density: effect on food intake and energy balance in free-living men eating ad libitum

Am J Clin Nutr. 1995 Aug;62(2):330-7. doi: 10.1093/ajcn/62.2.330.


We previously increased the energy density and fat content across three diets (factorial design), which led to a marked increase in energy intake in six men over 7 d while continuously resident in a whole-body indirect calorimeter. In the present study we fed the same diets to seven men who were resident in, but not confined to, a metabolic suite for 2 wk/diet. This added a component of increased physical activity. The fat, carbohydrate, and protein contents, respectively, of each diet (as a percent of energy) were as follows: low-fat (LF), 20:67:13; medium-fat (MF), 40:47:13; and high-fat (HF), 60:27:13. Energy density increased as the percent of fat in the diet increased. Energy intakes from the LF, MF, and HF diets (9.11, 10.32, and 12.78 MJ/d, respectively) were almost identical to those in our calorimeter study (9.02, 10.2, and 12.35 MJ/d, respectively) whereas energy expenditures (estimated by the doubly labeled water method) were 12.45, 12.10, and 11.97 MJ/d on the LF, MF and HF diets, respectively, compared with 9.48, 9.53, and 9.78 MJ/d, respectively, in our calorimeter study. This finding suggests that diet composition and energy expenditure combined influence energy balance in humans.

Publication types

  • Clinical Trial
  • Comparative Study
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Calorimetry, Indirect
  • Carbon Dioxide / metabolism
  • Deuterium
  • Dietary Carbohydrates / administration & dosage*
  • Dietary Fats / administration & dosage*
  • Eating / physiology*
  • Energy Intake / physiology
  • Energy Metabolism / physiology*
  • Exercise / physiology
  • Feeding Behavior / physiology*
  • Humans
  • Male
  • Methods
  • Middle Aged
  • Oxygen Isotopes
  • Satiation / drug effects
  • Satiation / physiology
  • Time Factors


  • Dietary Carbohydrates
  • Dietary Fats
  • Oxygen Isotopes
  • Carbon Dioxide
  • Deuterium