(P06-001-24) Validity of 24-Hour Physical Activity Recall To Estimate Total Daily Energy Expenditure in an Urban, Relatively Active Brazilian Adult Sample

Objectives: Total daily energy expenditure (TDEE) and basal metabolic rate (BMR) are used to estimate the energy requirements of populations. There are very limited available accurate data of these measures in low to mid income countries, primarily due to the high cost of objective methods to determine TDEE, such as the doubly labeled water (DLW) technique. The purpose of the study was to compare the TDEE assessed by a subjective (24-hour physical activity recall - 24hPAR, _24hPARTDEE) and the reference method of DLW (_DLWTDEE) in a sample of Brazilian adults living in the tropics.

Methods: A convenience sample of 40 adults (20-64y, 21 women) had anthropometric (body mass and stature), BMR and body composition data (DXA) collected in a visit to the laboratory. Prior to receiving the DLW dose, a baseline urine sample was obtained and subjects were instructed to collect an urine daily sample over the following 14 days. Four 24hPARs (2 face-to-face and 2 over the phone) were performed during this period and used to estimate TDEE with the conventional MET value of 3.5 mL O₂.kg^-1.min^-1 or a population-specific value (_NMET) and the MET codes from the 2024 updated version of the Compendium of Physical Activities (CPA). PAL (TDEE/BMR) was calculated using _DLWTDEE and measured BMR.

Results: Mean age and BMI (SD) were 30.4 (11.0) years and 23.1 (2.7), respectively. Mean BMR, TDEE, and PAL were 5598 (838), 9836 (2209) kJ.day^-1, and 1.75 (0.26). MET-estimated mean 24hPARTDEE (11567±2233) was significantly different from DLWTDEE for the group as a whole (p < 0.0001) and women (+2372±2122; 30%; p< 0.0001) and men (+1023±1715; 30%; 10%; p=0.02). However, TDEE was accurately estimated when _NMET was used for the whole group (9866±1762; 2.8%; p=0.914) and sex (women: +548±1589; 8.2%; p=0.130 and men: -543±1748; -3.2%; p=0.193).

Conclusions: The subjective method (24hPAR) provides accurate estimation of TDEE in this relatively active urban Brazilian adult sample when population-specific MET values and the 2024 CPA are used.

Funding Sources: CNPq (433760-2018-4 and 314885-2020-0) and CAPES (001)