The dysregulation of food intake in chronic obesity has been explained by different theories. To assess their explanatory power, we meta-analyzed 22 brain-activation imaging studies. We found that obese individuals exhibit hyper-responsivity of the brain regions involved in taste and reward for food-related stimuli. Consistent with a Reward Surfeit Hypothesis, obese individuals exhibit a ventral striatum hyper-responsivity in response to pure tastes, particularly when fasting. Furthermore, we found that obese subjects display more frequent ventral striatal activation for visual food cues when satiated: this continued processing within the reward system, together with the aforementioned evidence, is compatible with the Incentive Sensitization Theory. On the other hand, we did not find univocal evidence in favor of a Reward Deficit Hypothesis nor for a systematic deficit of inhibitory cognitive control. We conclude that the available brain activation data on the dysregulated food intake and food-related behavior in chronic obesity can be best framed within an Incentive Sensitization Theory. Implications of these findings for a brain-based therapy of obesity are briefly discussed.

慢性肥胖引起的食物摄入失调已经用不同的理论解释了。为了评估其解释力，我们对22项脑激活成像研究进行了荟萃分析。我们发现，肥胖的个体表现出大脑中与味觉和食物相关刺激有关的大脑区域的高反应性。与奖励冲浪假说相一致，肥胖的人对纯净的口味（特别是在禁食时）表现出腹侧纹状体的高反应性。此外，我们发现肥胖的受试者在满足时会表现出更频繁的腹侧纹状体激活，以获取视觉食物线索：这种在奖励系统中的持续处理以及上述证据与激励性敏化理论相吻合。另一方面，我们没有发现明确的证据支持奖励赤字假说，也没有发现抑制性认知控制的系统性缺陷。我们得出结论，关于慢性肥胖症中食物摄入失调和与食物相关的行为失调的可用大脑激活数据，可以在激励敏化理论中得到最好的构架。简要讨论了这些发现对基于脑的肥胖症治疗的意义。