Manipulating attention during eating effects food intake and medial prefrontal cortex fNIRS response in women with...

To investigate how shifting the attention away from food being eaten (by women who are cognitively restrained) toward another food-related stimulus affects food intake and relative increases in neural activity from baseline (as relative changes in oxygenated hemoglobin, HbO) within the medial prefrontal cortex (mPFC).

Participants were divided into 2 groups of 23 subjects based on a median split of TFEQ-R score: cognitively restrained (CR) or non-cognitively restrained (NCR). Relative change from baseline in mPFC activity was measured using functional near infrared spectroscopy (fNIRS) during ad libitum consumption of a preferred high fat/high sugar food over a 3- to10-min period while participants viewed food advertisement (FV) or nature scene (NV) videos.

After controlling for covariates, including body mass index and FV eating duration, we found that group-by-condition interaction was significantly able to predict grams of food consumed (P = 0.031). In the CR group, food intake positively correlated with mPFC HbO under both video conditions (P < 0. 05). The increase in mPFC HbO from baseline under both conditions was higher in CR subjects (P = 0.035, 95 % CI: 0.04, 1.20).

Exposure to a palatable food advertisement video elicited different behavioral and neural responses between CR and NCR groups. While food intake did not increase in the CR group under FV, their mPFC activity was positively correlated with intake. These findings suggest that maintaining restraint under hedonic distraction may require greater cognitive effort. Future studies should explore longer-term effects on self-regulation.