The psychological basis of obesity

Abstract This chapter provides an overview of the main and most consistently reported psychological factors that play a role in the onset and persistence of obesity. Taking psychological factors into account is crucial, as a pure biomedical model does not explain sufficiently the sizeable individual variability of weight gain and the persistence of abnormal weight. From a biopsychosocial perspective, we focus on eating behavior, how eating behavior is affected by psychological factors and the consequences of eating behavior. We discuss the role of emotional and cognitive factors, mood and emotional regulation, stigma and discrimination, and personality traits in relation to obesity. Studies show that individuals with obesity have a stronger sensitivity (attentional bias) for, and motivational drive (wanting) toward, foods rich in fat and sugar (palatable food) coupled with deficient impulse control in contexts of anticipated palatable food. Negative mood has been shown to be implicated in obesity and to induce compensatory (excessive) intake of palatable food. It should be noted that negative mood has a bidirectional relation with obesity; obesity has also been shown to result in negative mood. Certainly, adding to this is the fact that obesity is associated with stigma, discrimination, bullying, and stereotypical media portrayals. Importantly, it should be emphasized that there is a considerable overlap of the condition of obesity with addiction, both in terms of phenomenology and with respect to the brain mechanism that drives maladaptive behavior. Indeed, it has been suggested that obesity should be characterized as a mental disorder. Currently, obesity is not classified as a mental disorder mainly because of the heterogeneity and uncertainty with respect to its etiology. This may be surprising as this is the case with several other included disorders, and the debate continues. At least, part of the issue of current suboptimal treatment approaches is a lack of understanding of the key mechanism implicated in obesity. Hence, increased insight into the main psychological mechanisms could assist in future treatment directions.