Weekly changes in basal metabolic rate with eight weeks of overfeeding

Obesity (Silver Spring). 2006 Apr;14(4):690-5. doi: 10.1038/oby.2006.78.


Objective: The contribution of basal metabolic rate (BMR) to weight gain susceptibility has long been debated. We wanted to examine whether BMR changes in a linear fashion with overfeeding. Our hypothesis was that BMR does not increase linearly with 1000-kcal/d overfeeding in lean healthy subjects over 8 weeks. The null hypothesis states that BMR increases linearly with 1000-kcal/d overfeeding in lean healthy subjects.

Research methods and procedures: Initially, 16 lean healthy sedentary subjects completed 2 weeks of weight maintenance feeding at the General Clinical Research Center. The subjects were then overfed by 1000 kcal/d over 8 weeks. BMR was measured under standard conditions each week using indirect calorimetry.

Results: Baseline BMR was 1693 +/- 154.5 kcal/d. BMR increased from 1711 +/- 201.3 kcal/d at week 1 of overfeeding to 1781 +/- 171.65 kcal/d at the second week of overfeeding (p = 0.05). BMR fell during the third week of overfeeding to 1729 +/- 179.5 kcal/d (p = 0.05). After 5 weeks of overfeeding, BMR reached a plateau. Thereafter, there was no further change. Comparison of BMR with weeks of overfeeding was significantly different compared with the linear model (p < 0.05).

Discussion: Increases in BMR in lean sedentary healthy subjects with 1000-kcal/d overfeeding are not linear over 8 weeks. There seems to be a short-term increase in BMR in the first 2 weeks of overfeeding that is not representative of longer-term changes.

Publication types

  • Clinical Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adiposity
  • Adult
  • Basal Metabolism / physiology*
  • Body Fat Distribution
  • Body Mass Index
  • Body Weight
  • Calorimetry, Indirect / methods
  • Feeding Behavior / physiology*
  • Female
  • Humans
  • Male
  • Overnutrition / metabolism*