Does physical activity level and total energy expenditure relate to food intake, appetite, and body composition in healthy older adults? A cross-sectional study

Purpose: With ageing, older adults (≥ 65 years) may experience decreased appetite, contributing to declines in body weight and muscle mass, potentially affecting physical capabilities. Physical activity (PA) has been suggested as a potential strategy to enhance appetite in older adults, but evidence supporting this is insufficient. This study aimed to investigate the relationship between PA levels, total energy expenditure (TEE), body composition, energy intake (EI) and appetite in older adults. Methods: One hundred and eight healthy older adults (age 70 ± 4 years; BMI 24.3 ± 2.6 kg/m²) were categorised into three groups (low, medium, high) based on accelerometer-measured PA level (AMPA) and TEE from 7-day PA diaries. Body composition was measured using bioelectrical impedance. Energy and nutrient intakes were assessed using 3-day weighed food diaries. Appetite was assessed using the visual analogue scales at 30-min intervals throughout 1 day. Results: TEE was positively correlated with EI and % muscle mass (p < 0.05), with higher % muscle mass and TEE associated with higher EI. Energy and protein intake were significantly higher in the high TEE group than the low group (p = 0.03, p = 0.01; respectively). No significant differences in energy and macronutrient intake were observed across AMPA groups, and appetite components (hunger, fullness, desire to eat, prospective consumption) did not differ significantly in either the AMPA or TEE groups. Conclusions: Higher TEE is associated with higher energy and protein intake, with body composition playing a crucial role. These findings highlight the importance of considering PA, TEE, and body composition in interventions aimed at improving EI in older adults. Clinical Trail registration: clinicaltrials.gov as NCT05067036. Registered 2 October 2021, https://classic.clinicaltrials.gov/ct2/show/NCT05067036