Effects of energy imbalance on energy expenditure and respiratory quotient in young and older men: A summary of data from two metabolic studies
The roles of energy expenditure and substrate oxidation in energy regulation, and the effects of factors such as aging on these parameters, remain uncertain. A re-analysis of data from two studies involving overfeeding or underfeeding in young men (22.7±0.6 [SEM] years) and older men (68.0±1.50 years) was conducted to further evaluate the adaptive capacity of energy expenditure and respiratory quotient to an increase or a decrease in energy intake. Changes in total energy expenditure (TEE) and resting energy expenditure (REE) and respiratory quotient (RQ) in response to energy imbalance were compared between subjects undergoing overfeeding by 4.1MJ/day for 21 days, or underfeeding by 3.2 MJ/day for 21 days. Comparing responses to overfeeding or underfeeding, there was a significant TEE response to energy imbalance averaging 1.39 MJ/day and equivalent to 19% of the alteration in energy intake (p<0.05). There was also a significant REE response to energy imbalance averaging 0.45 MJ/day (p<0.001), and a significant RQ response in both fasting and fed states (p<0.01). There was no significant difference between young and older men in their TEE, energy deposition or RQ responses to energy imbalance, but older men did have significantly diminished REE response to energy imbalance (p<0.05) and a significantly delayed thermic response to a standard meal (p<0.05). These data indicate that energy expenditure plays a significant role in attenuating the effects of alterations in energy intake on body energy stores and that, based on some measures of energy expenditure, aging is associated with a reduction in the adaptive capacity of energy expenditure to participate in energy regulation.
Key wordsAging carbohydrate energy metabolism fat
Unable to display preview. Download preview PDF.
- 3.Roberts S.B.: Use of the doubly labeled water method for measurement of energy expenditure, total body water, water intake, and metabolizable energy intake in humans and small animals. Can. J. Physiol. Pharm. 67: 1191–1198, 1989.Google Scholar
- 10.Roberts S.B., Fuss P., Dallal G.E., Atkinson A., Evans W.J., Joseph L., Fiatarone M.A., Greenberg A.S., Young V.R.: Effects of age on energy expenditure and substrate oxidation during experimental overfeeding in healthy men. J. Gerontol., 1996 (in press).Google Scholar
- 11.Roberts S.B., Fuss P., Heyman M.B., Dallal G.E., Young V.R.: Effects of age on energy expenditure and substrate oxidation during experimental underfeeding in healthy men. J. Gerontol., 1996 (in press).Google Scholar
- 13.Roberts S.B., Young V.R., Fuss P., Heyman M.B., Fiatarone M.A., Dallal G.E., Evans W.J.: What are the dietary energy needs of elderly adults? Int. J. Obesity 16: 969–976, 1992.Google Scholar
- 16.Committee on Diet and Health, Food and Nutrition Board, Commission on Life, National Research Council.: Diet and health: Implications for reducing chronic disease. National Academy Press, Washington, DC, 1989.Google Scholar
- 22.Pace N., Rathburn E.N.: Studies on body composition. III. The body water and chemically combined nitrogen content in relation to fat content. J. Biol. Chem. 158: 685–691, 1945.Google Scholar
- 23.Garrow J.S.: Energy balance and obesity in man. North Holland Publishing Co., Amsterdam, 1974.Google Scholar
- 24.Gulick, A.: A study of weight regulation in the adult human body during over-nutrition. Am. J. Physiol. 60: 371–395, 1922.Google Scholar
- 28.Tzankoff S.P., Norris A.H.: Longitudinal changes in basal metabolic rate in man. J. Appl. Physiol. 33: 536–539, 1978.Google Scholar