Conscious and pre-conscious attentional bias to food images in patients subjected to Roux-en-Y gastric bypass

Abstract

Attentional bias (AB) to food after bariatric surgery might be a cognitive marker for weight regain. The visual probe task (VPT) is commonly used to capture AB at automatic, pre-conscious, and conscious orientation of attention. The aim of this study was to investigate how the preoperative BMI of patients submitted to Roux-en-Y gastric bypass (RYGB) impacts AB to food. We assessed patients who had preoperative BMI>50 (n = 28) or preoperative BMI<50 (n = 31) months after the RYGB procedure. Participants underwent clinical, psychological, and VPT evaluations. In VPT, pairs of food and matching non-food images were shown for 100 ms, 500 ms or 2000 ms and AB for food was assessed for each exposure time. A significant AB to food was observed at 2000 ms for all patients in this study, suggesting that the overall sample were consciously orienting their attention toward food cues after surgery, a finding that might be relevant for understanding weight control. When groups with preoperative BMI higher and lower than 50 kg/m² were compared, a significant difference on AB to food stimuli at 500 ms was observed, controlling for excess weight lost since surgery and postoperative time. Subjects with preoperative BMI>50 had a positive and reliable AB to food while subjects with preoperative BMI<50 had a negative AB. This suggests that food stimuli have a higher incentive salience even after surgery for those with BMI>50, which might explain why subjects with higher preoperative weight have higher risks for weight regain. These results may indicate that RYGB can impact incentive salience for food cues in a differential manner, increasing conscious AB in all patients and decreasing pre-conscious AB only in those with BMI<50 kg/m².

Keywords: Atentional bias; Bariatric surgery; Obesity.