Using Time-Weighted Averages of Total Daily Energy Expenditure to Estimate Energy Intake During a Weight Loss Intervention

Abstract

Objective: The doubly labeled water (DLW) intake-balance method estimates energy intake (EI) during weight loss using the time-weighted average of total daily energy expenditure (TDEE) and changes in body energy stores. Because TDEE declines rapidly during the early phase of weight loss, an early additional measurement is recommended. This study aimed to develop regression models that estimate time-weighted TDEE using fewer interim measurements and determine if EI accuracy is maintained during a 12-month weight loss intervention.

Methods: Data from a behavioral weight loss intervention (Dietary Caloric Restriction versus intermittent Fasting Trial, "DRIFT") were used. TDEE, body weight, and body composition were measured at months 0, 1, 6, and 12. Regression models using only two or three time points were used to estimate time-weighted TDEE at months 6 and 12, respectively. Models were validated using bootstrap sampling, and time-weighted TDEE and percent caloric restriction (% CR) were compared to a reference approach.

Results: Models demonstrated strong predictive performance (R ² = 0.911-0.982). Limits of agreement with the reference model were 121.1-274.5 kcal/day for TDEE and 4.5%-10.3% for % CR, without significant bias.

Conclusions: Using a regression modeling approach, we demonstrate the DLW intake-balance method maintains accuracy during weight loss without early-phase TDEE measurements.

Trial registration: ClinicalTrials.gov identifier: NCT03411356.

Keywords: calorie restriction; doubly labeled water; energy balance; intake‐balance method; metabolic adaptation.

Figure 1.

Participant flow diagram and study timeline for secondary analysis. Abbreviations are as follows: 4:3 Intermittent Fasting (4:3 IMF); Daily Caloric Restriction (DCR); Doubly Labeled Water (DLW); Dual-energy X-ray Absorptiometry (DXA); Total Daily Energy Expenditure (TDEE); Months 0, 1, 6, and 12 (M0, M1, M6, and M12).

Figure 2.

Changes in body weight, body composition, and TDEE after 1, 6, and 12 months. A. Data (n=50) used to develop the 6M-Ref and Model 1. B. Data (n=47) used to develop the 12M-Ref and Models 2 – 4. ^a Results (mean ± SD) are from linear mixed effects model with unstructured covariance.

Figure 3

Legend. Bland-Altman comparisons of the time-weighted average of TDEE computed using the regression models and reference approaches. Time points include M0, M1, M6, and M12. A. Model 1 (M0 and M6 TDEE) vs 6M-Ref, B. Model 2 (M0 and M12 TDEE) vs 12M-Ref, C. Model 3 (M0, M1, and M12 TDEE) vs 12M-Ref, and D. Model 4 (M0, M6, and M12 TDEE) vs 12M-Ref.

Figure 3

Legend. Bland-Altman comparisons of the time-weighted average of TDEE computed using the regression models and reference approaches. Time points include M0, M1, M6, and M12. A. Model 1 (M0 and M6 TDEE) vs 6M-Ref, B. Model 2 (M0 and M12 TDEE) vs 12M-Ref, C. Model 3 (M0, M1, and M12 TDEE) vs 12M-Ref, and D. Model 4 (M0, M6, and M12 TDEE) vs 12M-Ref.