Can Routine Clinical Tests for Protein Intake and Physical Function Predict Successful Weight Loss?

Background: Protein intake and physical activity have a substantial impact on body composition and weight loss outcomes after bariatric surgery. The 24-h dietary recall and 6-min walk test (6mWT) are frequently used to monitor protein intake and physical activity, respectively. Despite its frequent use, it is unknown whether these tests can predict long-term weight loss. Methods: This retrospective study included 85 patients who underwent laparoscopic Roux-en-Y gastric bypass. Protein intake was recorded using the 24-h dietary recall and physical function was measured using the 6mWT. Data about total weight loss (TWL) and nonresponse (i.e., insufficient weight loss and weight regain) were collected up to 5 years. Multiple regression analyses were performed to examine the predictive value of the 24-h dietary recall and 6mWT on weight loss outcomes. Results: The mean protein intake 1 year postoperatively was 68.1 +/- 15.0 g/day and the mean distance covered during the 6mWT was 591.7 +/- 67.9 m. Both the 24-h dietary recall and 6mWT were not significantly associated with TWL and neither with nonresponse. Conclusions: The 24-h dietary recall and 6mWT are poor predictors for long-term weight loss outcomes after gastric bypass. Despite the well-known advantages of these clinical tests, other monitoring tests are suggested for future research.