Fat Taste Sensory Study

Overview

Fat is the most energy dense macronutrient and consuming fat has been positively correlated to obesity. Individuals afflicted with obesity crave fat more frequently, have a higher preference for fatty taste, and consume a higher quantity of fatty foods. People who have undergone Roux-en-Y Gastric Bypass (RYGB) or Sleeve Gastrectomy (SG) weight-loss surgeries dramatically decrease their fat preferences and consumption of fat, at least within the first year after surgery. These surgeries are very effective in helping people lose weight over the first couple of years; however, approximately 30% of those who undergo these surgeries start regaining weight after the second year mark. Why some people are able to keep the weight off long-term but others are unable to is unclear. In addition, it is well-known that fat can modify the flavor of foods and flavor plays a critical role in consumption, as well as in responses that gear up the body to consume the food. These are known as cephalic phase responses and include neural, physiological, and hormonal aspects. The main goals of the study are twofold: 1) To test the immediate effects of RYGB surgery, SG surgery, and laparoscopic gastric banding (LAGB) surgery (a weight loss control group) on fat preferences and sensory perception, and 2) to compare fat preferences and sensory perception between those who are able to achieve sustained weight loss 2-5 years after RYGB or SG surgery and those who either regained weight or did not lose the desired amount.

For the first goal, the investigators will assess a longitudinal group of subjects both before RYGB surgery (n=15) SG surgery (n=15), and LAGB surgery (n=15), and then again after they lose \~16% of their body weight post-surgery in the fed and the fasted state. the investigators will also study the same variables in a cross-sectional design consisting of two groups: a weight success group (n=30) and a weight failure group (n=30) 2-5 years post RYGB or SG surgery. The weight success group will include subjects who lost ≥40% body weight by 2-5 years post-surgery and the weight failure group will include subjects who lost \<25% body weight by 2-5 years post-surgery. In addition, the investigators will also explore the extent to which fat preferences and sensory perception in these subjects are affected by flavor related genes.