Objectives: Decreased energy intake in older persons poses these people at risk of progressive weight loss. It may result from a failure to regulate energy intake and expenditure after periods of underfeeding. The objective of this study was to investigate if a period of underfeeding differentially influences energy intake of older compared with young men and, additionally, to study potential underlying mechanisms, namely changes in gastric emptying rate and cholecystokinin (CCK) levels in blood.
Design/setting: Dietary intervention of 3 phases. After a phase of energy balance, we fed participants in phase 2 by a mean of 70% of their needs for 21 days. During phase 3, we assessed ad libitum energy intake of the participants during 9 days. At the end of phases 1 and 2, we assessed appetite, gastric emptying, and CCK levels in blood in response to a test meal.
Participants: Fifteen young (age 24 years [range 20-34], body mass index 23.0 kg/m(2) ± 2.3) and 17 older (age 68 years [64-85], body mass index 24.5 kg/m(2) ± 1.9) men participated in this study.
Results: During energy balance, mean energy intake of young men (14.3 ± 2.3 MJ/day) was significantly higher than that of older men (11.3 ± 1.8 MJ/day, P < .001). After the period of underfeeding, energy intake in phase 3 amounted to 16.3 ± 2.6 MJ/day in young men and to 14.4 ± 3.2 MJ/day in older men. Ad lib energy intake after underfeeding did not differ between young and older men (analysis of covariance, with energy intake during phase 1 as covariate, P = .99). There were no differential changes in body weight, body composition, resting energy expenditure, gastric emptying rate, CCK-8 levels, and appetite between young and older men during the study.
Conclusion: Our results do not indicate that older men have an impaired ability to control energy intake after a period of underfeeding compared with younger men.
Trial registration: NCT00561145.
Copyright © 2011 American Medical Directors Association. Published by Elsevier Inc. All rights reserved.