Influence of Activity Levels and Energy Intake on Percent Excess Weight Loss After Roux-En-Y Gastric Bypass

BACKGROUND: Gastric bypass is a successful medical intervention for weight loss for obesity. Weight loss is substantial after this surgery. Predictors of the most successful weight loss are not yet fully known. The purpose of this study was to define variables that improve percent excess weight loss (%EWL) in this post-surgical population. METHODS: All patients who underwent the Roux-en-Y gastric bypass (RYGB) during the 5 years preceding the study in one surgical practice (n = 805; respondents = 265; 33%) received the Arizona Activity Frequency Questionnaire and the Arizona Food Frequency Questionnaire. Analysis through ANOVA testing to determine relationships between selected behaviors and %EWL was performed. RESULTS: Comparisons of differences in mean %EWL were analyzed using the variables of energy consumption/day (energy consumption), hours of activity/day (hours in activity), and energy expended in activity/day (energy expended). Patients with more energy expended, and hours in activity demonstrated significantly better %EWL (p = 0.05) when compared to those with less energy expended or hours in activity. Reported energy consumption did not significantly influence %EWL in this study. CONCLUSIONS: This research suggests that in this sample of post-RYGB patients, energy expended in activity, as either energy expended or hours in activity improved their %EWL over those persons not expending as much energy in activity. Increasing the hours in activity improved the maintenance of %EWL in these respondents. Energy consumption did not have a statistically significant effect on %EWL or maintenance of %EWL in these subjects