Dietary self-monitoring versus ecological momentary assessment in measuring and characterizing dietary lapses.

Dietary lapses in behavioral weight loss (BWL) programs, i.e., non-adherence to the dietary prescription, impede weight loss. Ecological momentary assessment (EMA; brief, repeated surveys) has many strengths in measuring lapses, but may underestimate lapse frequency and does not easily capture lapses' nutritional make-up. Dietary self-monitoring may offer benefits over EMA in measuring lapses, though this remains unstudied. We hypothesized EMA would underestimate lapses relative to dietary self-monitoring, and dietary self-monitoring would reveal lapses were associated with higher calories, higher percent fat and carbohydrate, and lower percent protein, relative to non-lapses. Participants were adults with overweight/obesity (N = 104) in a 12-week remote BWL program. Participants were prescribed an individualized daily calorie goal that was divided into calorie targets for meals/snacks; exceeding those targets constituted a lapse. Participants completed dietary self-monitoring in MyFitnessPal Premium (MFP) and 6 daily EMAs for 2 weeks at baseline, mid-treatment, and end-of-treatment. Participants reported more daily lapses via MFP (∼1.6) than EMA (∼0.5). Lapses contained ∼230 more calories, 5% more fat, 2% less protein, and 3% less carbohydrate than non-lapses on average, controlling for meal/snack type. Exploratory aims found lapse days measured by MFP and EMA were associated with greater calorie intake than non-lapse days; however, only average daily lapses measured by MFP (not EMA) predicted estimated percent weight change. In conclusion, EMA underestimated daily lapses by ∼69% relative to MFP, and MFP revealed lapses had meaningful increases in calories and fat relative to non-lapses. Findings can inform BWL program modifications, e.g., increased focus on monitoring/limiting high-fat foods.