Background: Energy intake (EI) regulation is impaired in older adults, but it is not known if habitual physical activity affects accuracy of EI regulation in older compared with young adults. Objective: We hypothesized that the ability to compensate for a high-energy yogurt preload beverage at a subsequent ad libitum meal (i.e. acute compensation) and over the course of the testing day (i.e. short-term compensation) would decrease with age, but the magnitude of the decline would be smaller in physically active compared with sedentary older adults. Design: On two occasions, young active (n ¼ 15), young sedentary (n ¼ 14), older active (n ¼ 14) and older sedentary (n ¼ 11) subjects consumed either a high-energy yogurt preload beverage (YP: 500 ml, 1988 kJ, men; 375 ml, 1507 kJ, women), or no preload (NP), 30 min before an ad libitum test meal. EI at both ad libitum meals was measured, and total daily EI was determined on both testing days. Percent EI compensation for the YP was calculated for the test meal and testing day to determine acute and short-term compensation. Results: Percent EI compensation at the test meal was significantly lower in the older compared with the young subjects (6574 vs 8174%, P ¼ 0.005). There was no effect of habitual physical activity level on acute compensation, and no age by physical activity level interaction (P ¼ 0.60). In contrast, short-term compensation was not different with age (8775 vs 9376%, older vs young, P ¼ 0.45), but was more accurate in active vs sedentary subjects (10075 vs 7976%, P ¼ 0.01). As with acute compensation, there was no age by physical activity interaction (P ¼ 0.39). Conclusion: Acute EI regulation is impaired in older adults, which is not attenuated by physical activity status. However, EI regulation over the course of a day is more accurate in active vs sedentary adults, which may facilitate long-term energy balance. Future work is needed to determine if higher energy expenditure in older active vs older sedentary adults improves long-term EI regulation.

VAN WALLEGHEN, EMILY, JEB S. ORR, CHRIS L. GENTILE, AND BRENDA M. DAVY. Pre-meal water consumption reduces meal energy intake in older but not younger subjects. Obesity. 2007;15:93-99. Objective: To determine whether the consumption of water 30 minutes before an ad libitum meal reduces meal energy intake in young and older adults. Research Methods and Procedures: Healthy, non-obese young (n ϭ 29; age, 21 to 35 years) and older (n ϭ 21; age, 60 to 80 years) individuals were provided with an ad libitum lunch meal on two occasions. Thirty minutes before the lunch meals, subjects were given either a water preload (WP: 375 mL, women; 500 mL, men) or no preload (NP). Energy intake at the two lunch meals was measured. Visual analog scales were used to assess changes in hunger, fullness, and thirst during the meal studies. Results: There was no significant difference in meal energy intake between conditions in the young subjects (892 ϩ 51 vs. 913 Ϯ 54 kcal for NP and WP, respectively; p ϭ 0.65). However, meal energy intake after the WP was significantly reduced relative to the NP condition in the older subjects (682 ϩ 53 vs. 624 Ϯ 56 kcal for NP and WP, respectively; p ϭ 0.02). This effect was caused primarily by the reduction in meal energy intake after water consumption in older men. Hunger ratings were lower and fullness ratings were higher in older compared with younger adults (p Ͻ 0.01). Fullness ratings were higher in the WP condition compared with the NP condition for all subjects (p ϭ 0.01). No age differences in thirst were detected during the test meals. Discussion: Under acute test meal conditions, pre-meal water consumption reduces meal energy intake in older but not younger adults. Because older adults are at increased risk for overweight and obesity, intervention studies are needed to determine whether pre-meal water consumption is an effective long-term weight management strategy for the aging population.

Background: To compare the effects of low versus recommended levels of dairy intake on weight maintenance and body composition subsequent to weight loss.

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