Thermic effect of feeding in relation to energy balance in elderly men.

Resting metabolic rate (RMR) and the thermic effect of feeding (TEF) two meals of differing energy densities were measured in 8 healthy elderly men aged 63-74 years. Similar measurements were made on 8 healthy young men aged 22-28 years. TEF was related to the meal size in both groups. Metabolic rate increased by 20.7 and 27.9% in the elderly group (EG) and 25.8 and 37.7% in the control group (CG) in response to the 2.0-and 4.0-MJ meals, respectively. Although the EG were fatter than the CG, they consumed a smaller daily food intake: we suggest that the decline in RMR and TEF as indicated by the study would explain his paradox.