Underreporting of energy intake in weight loss maintainers.
Level 4 - case-series / case-control
Case-control observational study comparing three distinct cohorts
PubMed 33742193 · doi:10.1093/ajcn/nqab012
What was done
This case-control study compared the accuracy of self-reported energy intake (EI) across three groups: successful weight loss maintainers (WLM; n = 26, BMI 24.1 ± 2.3 kg/m², maintaining ≥13.6 kg weight loss for ≥1 year), normal-weight controls (NC; n = 33, BMI 22.7 ± 1.9 kg/m²), and controls with overweight/obesity (OC; n = 32, BMI 34.0 ± 4.6 kg/m²). Total daily energy expenditure (TDEE) was measured over 7 days using the doubly labeled water (DLW) method, and self-reported EI was measured concurrently using 3-day diet diaries.
What was found
WLM underreported daily EI by a median (IQR) of -605 (-915 to -314) kcal/d, which was significantly greater than NC (-308, -471 to -68 kcal/d; P < 0.01) but not significantly different from OC (-310, -970 to 18 kcal/d; P = 0.21). In relative terms, WLM underreported by -25.3% (-32.9% to -12.5%) compared with -14.3% (-19.6% to -3.1%) in NC (P = 0.02) and -11.2% (-34.1% to -0.7%) in OC (P = 0.16). A higher proportion of WLM were categorized as underreporters (30.8%) compared with NC (9.1%; P = 0.05), with no difference compared to OC (28.1%; P = 1.00).
Why it matters
Self-reported diet diaries in weight loss maintainers substantially underestimate actual caloric intake, challenging prior literature that attributed long-term maintenance primarily to severe chronic caloric restriction rather than higher energy expenditure.
Limits
The sample size was relatively small (n = 26 to 33 per group). Diet was captured over a 3-day diary window while energy expenditure was assessed over 7 days. Findings rely on cross-sectional group comparisons without longitudinal dietary tracking from before weight loss.
Cited by
- partial Scientific studies consistently show that people underreport their calorie intake by 30% to 50%.