Fat-Free Mass and Total Daily Energy Expenditure Estimated using Doubly Labelled Water Predict Energy Intake in a Large Sample of Community-Dwelling Older Adults

Background

Up to 30% of community-based older adults report reduced appetite and energy intake (EI), but previous research examining the underlying physiological mechanisms have focused on the mechanisms that suppress eating rather than the hunger drive and EI.

Objective

To examine the associations between fat-free mass (FFM), physical activity (PA), total daily energy expenditure (TDEE) and self-reported EI in older adults.

Methods

The present study was a secondary analysis of The Interactive Diet and Activity Tracking in AARP Study. Body composition (deuterium dilution), PA (accelerometry) and TDEE (doubly labelled water) were measured in 590 older adults (age = 63.1 ± 5.9 years; BMI = 28.1 ± 4.9 kg/m2). Total daily EI was estimated from a single 24-hour dietary recall (EIsingle; ± one month of PA and TDEE measurement) and the mean of up to six recalls over a 12-month period (EImean), with mis-reporters classified using the 95% confidence intervals between EImean and TDEE.

Results

After controlling for age and sex, linear regression demonstrated that FFM and TDEE predicted EI when estimated from a single 24-hour dietary recall (p < 0.05), the mean of up to six dietary recalls (p < 0.05) and after the removal of those classified as under-reporters (p < 0.001). Age moderated the associations between FFM and EIsingle (p < 0.001), FFM and EImean (p < 0.001), and TDEE with EIsingle (p = 0.016), with associations becoming weaker across age quintiles.

Conclusions

These data suggest that total daily EI is proportional to FFM and TDEE, but not fat mass, in older adults. These associations may reflect an underling drive to eat that influences daily food intake. While the associations between FFM or TDEE and EI existed across all age quintiles, these associations weakened with increasing age.

Trial Registration

The Interactive Diet and Activity Tracking in AARP (IDATA) Study was registered at clinicaltrials.gov as: NCT03268577 (http://www.clinicaltrials.gov).