Estimated vs. actual resting energy expenditure and physical activity factor in post‐gastric bypass, lean and obese adults

Abstract

Resting energy expenditure (REE) equations multiplied by a predetermined physical activity factor (PAF) are commonly used to determine energy requirements However, estimated vs. actual REE and PAF among post‐gastric‐bypass surgery (GBS), obese (Ob) and lean (L) adults have not been compared. We hypothesized that GBS, Ob and L adults will have: 1) actual REE lower than estimated and 2) actual PAF lower than estimated. A group of 13 GB, 15 Ob and 11 L adults completed REE measurements by indirect calorimetry following standard clinical procedures. The Harris‐Benedict equation (HB) and pre‐determined PAF were used to estimate energy requirements. Physical activity energy expenditure (PAEE) was determined with accelerometry and PAF with the equation: (Actual REE + accelerometry PAEE)/Actual REE. Two‐way ANOVAs were used to detect differences by group and method, and agreement between methods using Bland & Altman plots. Group differences in actual REE (1631±174, 1830±290, 1441±151 kcal/day, respectively; P<0.01) and HB REE (1600±131, 1970±274, 1542±225 kcal/day, respectively, P<0.01) were observed, with no differences by method. Actual PAEE (269±70, 365±98, 228±112 kcal/day, respectively, P=0.002) yielded PAF ranging from 1.1 to 1.3, while HB PAF ranged from 1.2 to 1.7; causing higher predicted vs. actual energy requirement in all groups. While HB REE appeared adequate, predetermined PAF are not recommended.