Taste and smell in weight loss surgery

Metabolic surgeries are the most effective weight loss treatment for severe obesity and its related comorbidities such as diabetes and hypertension. These surgical procedures promote many physiological and ingestive behavioral changes that are not fully understood. In particular, preference for unhealthy foods after metabolic surgeries is reduced both in patients in the clinic and in preclinical models. It is hypothesized that the reduced preferences or consumption for high-sugar/fat foods is possibly due to what patients commonly describe as alterations in their "taste" perception. This chapter reviews studies that assessed taste and smell changes associated with metabolic surgeries, focusing mainly on those that used sensory evaluation techniques. Findings from these studies have been inconsistent and, overall, the evidence that metabolic surgeries change taste sensitivity is weak. However, findings on the effects of these surgeries on the affective or hedonic component of flavor perception have been more consistent and are congruent with findings from preclinical studies revealing surgery-related changes in central circuits of reward. More studies are needed to elucidate the mechanisms underlying these post-surgical alterations in the rewarding value of food.