Evaluation of new predictive equations for energy requirements in older adults: A comparison with doubly labeled...

The National Academies of Sciences, Engineering, and Medicine recently updated the Dietary Reference Intakes (DRIs) for Energy using doubly labeled water (DLW) data from several international studies. The lack of energy estimation equations for older adults remains a knowledge gap. Therefore, recent specific equations for this age group have been suggested, such as the proposed by Porter et al. This study aimed to evaluate the accuracy of two new equations developed for estimated energy requirements in older adults.

Data were obtained from a cross-sectional study with weight-stable older adults. Resting energy expenditure (REE) was measured using indirect calorimetry. Total energy expenditure (TEE) was assessed by DLW. Estimated energy requirements (EER) were calculated using predictive equations from the National Academies of Sciences, Engineering, and Medicine (EER-NASEM) and Porter et al. (EER-Porter). Accuracy between methods was evaluated using bias in percentage, root mean squared error in percentage (RMSE%), Pearson's correlation, Bland-Altman plots, and at the individual level with ±10 % of TEE obtained by DLW.

This study included 41 volunteers (21 women). The mean DLW-TEE was 2006 (SD = 366) kcal/day for women and 2420 (606) kcal/day for men. EER-NASEM was 1865 (186) kcal/day for women and 2396 (247) kcal/day for men. EER-Porter was 1893 (218) kcal/day for women and 2357 (312) kcal/day for men. Both equations had a mean bias of ≤10 % of the measured TEE by DLW but with an RMSE% ≥ 10 %. At the individual level, EER-NASEM overestimated measured TEE in 35.0 % of men and underestimated in 23 % of women. In contrast, EER-Porter showed a 15 % overestimation for men and an underestimation in 28 % of women.

According to our results, these equations should be used with caution in clinical practice at the individual level. A tailored approach to individual context, particularly whether the priority is to prevent obesity or underweight, as well as the assessment of energy intake, physical activity levels, and changes in body weight changes is crucial to dietary planning and preventing unintentional weight changes in older adults.