Abstract:

Food is a natural rewarding stimulus, which promotes human to seek for it because of their instinctive desire and need for reward. “Wanting”, “liking” and “learning & reinforcement” are three main components of food reward, and each of them is represented in its corresponding neural pathway. Food reward regulates food intake behavior and body weight. The association between food reward and obesity has predominantly been explained by three main theoretic models, namely the incentive sensitization theory of addiction, the reward-surfeit theory of obesity and the reward deficit theory of obesity. In human studies, the association between food reward and obesity has usually been studied by using a cross-sectional design, perspective design or longitudinal within-subjects design, in which either food pictures or palatable liquid foods (such as milkshake) were used as the experimental stimuli to obtain brain responses to food cues or actual foods, respectively. In addition, human brain response to both food cues and actual foods is regulated by the human genome. The role of single nucleotide polymorphisms (SNPs) in dopamine D2 receptor gene TaqIA rs1800497 and the FTO gene rs9939609 is discussed in the current review.

Key words: obesity, food reward, fMRI, TaqIA, FTO