Development of adherence metrics for caloric restriction interventions

Area of Science:

• Nutrition science
• Obesity research
• Biostatistics

Background:

• Objective measures are crucial for quantifying dietary adherence during free-living caloric restriction (CR).
• Comparing observed weight loss to expected weight loss, predicted by mathematical models, is a key method for monitoring adherence.
• Normograms, derived from these models, can assist counselors in guiding participants toward their caloric targets.

Purpose of the Study:

• To develop predictive models for weight loss over one year of CR, incorporating demographics, body mass index, total daily energy expenditure (TDEE), and percentage of CR (%CR).
• To create normograms based on these models to visualize expected weight loss trajectories for individuals undergoing CR.

Main Methods:

• Seventy-seven participants in a 6-12-month CR intervention (CALERIE) had frequent body weight and composition measurements.
• Energy intake (%CR) was estimated using TDEE (doubly labeled water) and body composition (DXA) at multiple time points.
• Statistical modeling was employed to identify predictors of the expected percent weight change trajectory over 12 months of CR.

Main Results:

• Weight change during CR was significantly related to adherence to the prescribed regimen.
• Predictors of the percent weight change trajectory included age, TDEE, %CR, and sex, modeled using nonlinear functions.
• Normograms indicated an average 12-month weight loss of -10.9% for females and -13.9% for males adhering to a 25% CR regimen.

Conclusions:

• Weight change trajectories during CR can be modeled using nonlinear functions of key covariates like CR level, TDEE change, gender, and age.
• Individually tailored normograms can serve as valuable tools for both counselors and participants to track weight loss and adherence.
• Limitations include small sample size and potential lack of generalizability to broader populations.