Introduction: Growing researches have shown that obese/overweight and healthy weight individuals exhibit different neural responses to food-related stimuli. Accordingly, researchers proposed several theories to explain these differences. Hereon, meta-analyses were conducted using activation likelihood estimation (ALE) to verify these theories and specify the reason of overeating from two aspects.
Materials and methods: Pubmed, Web of Science and Neurosynth were searched for the current study and screened according to inclusion criteria. Firstly, neural responses to visual food cues versus non-food images were compared between obese/overweight and healthy weight individuals. Then, neural activation to high-calorie food images versus low-calorie food/non-food visual stimuli was further investigated among the two populations. Coordinates in included studies were recorded and analysed by Ginger ALE software under threshold at uncorrected p < 0.001 with cluster-level p < 0.05 (cFWE).
Results: Eleven and seven studies were found in the first and second set of meta-analysis, respectively. The first meta-analysis showed that obese/overweight have hyper-responsivity in reward area and hypo-responsivity in both gustatory processing and inhibitory control area. The second meta-analysis indicated that the reward responsivity in the obese/overweight individuals was amplified and healthy weight individuals had higher activation in areas associated with gustatory processing in response to high-calorie food images.
Conclusions: Our results showed that the obese/overweight exhibit hyper-responsivity in brain regions involved in reward processing for visual food cue which provide strong support for incentive-sensitization theory of obesity and healthy weight individuals showed higher response in inhibitory control region which support the inhibitory control deficit theory of obesity.
Keywords: Inhibitory control; Neural activation; Reward processing; Visual food cues; obese/overweight.
Copyright © 2020 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.