Continued High Degree of Underreporting of Energy Intake among Bariatric Patients after Weight Loss

Background: Self-reported energy intake (EIn) is subject to underreporting in subjects with obesity. Adjustment for underreporting of EIn based on body mass index (BMI) has been suggested. Therefore, this study investigated EIn underreporting following weight loss in bariatric patients. Methods: There were 18 class III obese women (30 ± 5 years, 41-51 kg/m2) who underwent Roux-en-Y gastric bypass (RYGB) surgery and 62 reference participants (34 ± 6 years, 19-57 kg/m2, 47% female). Underreporting was expressed as a percent difference between the 24-h self-reported dietary recall and total energy expenditure (TEE) assessed by doubly labeled water assuming weight stability in the bariatric group before surgery and the reference population. Because RYGB patients were not weight stable, we also calculated EIn from TEE-change in body energy stores. Results: The underreporting error increased in the reference group as BMI rose (normal weight [-5%], overweight [-15%], class I obesity [-21%], class II [-26%], and class III obesity [-42%]). Underreporting by class III obese bariatric candidates (-50%) did not differ (p > 0.05) from the reference group for class III obesity. After weight loss, bariatric patients achieved class I obesity, but underreporting after six (-58%) and twelve (-55%) months of surgery remained the same as before surgery (p > 0.05) and were different from the class I obese in the reference group. Reported energy intake at six (-345kcal/ day, -20%) and twelve (968kcal/day, -44%) months after surgery remained underreported (p < 0.05) when compared to calculated EIn. Conclusions: Bariatric patients continued to underreport EIn at twelve months after surgery despite the change in BMI status. Our data indicates the correction of underreporting of EIn, based on BMI class should be used with caution after bariatric surgery.