The Role of Altered Nutrient Partitioning in Food Reward

Participants will consume flavored beverage solutions containing 75 calories of sucrose in 6 exposure sessions within 1 week. One exposure session will include pre- and post-consumption blood draws over a 2-hour period, and one exposure session will include indirect calorimetry measurement pre- and post-consumption. The other 4 exposure sessions will occur at specified times outside the laboratory sessions. Subjective ratings of internal state (i.e., hunger, fullness, and thirst) will be collected throughout each exposure. Subjective ratings of liking and wanting of each beverage will also be assessed.

Participants will consume flavored beverage solutions sweetened with sucralose to match the sweetness of 75 calories of sucrose in 6 exposure sessions within 1 week. One exposure session will include pre- and post-consumption blood draws over a 2-hour period, and one exposure session will include indirect calorimetry measurement pre- and post-consumption. The other 4 exposure sessions will occur at specified times outside the laboratory sessions. Subjective ratings of internal state (i.e., hunger, fullness, and thirst) will be collected throughout each exposure. Subjective ratings of liking and wanting of each beverage will also be assessed.

A high-fat test meal (60% fat, 20% carbohydrate) will be provided after a 1-hour baseline measurement of substrate oxidation during a 6-hour metabolic chamber stay. Postprandial substrate oxidation will be measured for 5 hours.

A high-carbohydrate test meal (60% carbohydrate, 20% fat) will be provided after a 1-hour baseline measurement of substrate oxidation during a 6-hour metabolic chamber stay. Postprandial substrate oxidation will be measured for 5 hours.

A subset of participants with BMI \> 25 will be invited to complete an functional magnetic resonance imaging (fMRI) scan as a feasibility measure. fMRI scans will be performed while beverages (without calories) used during the intervention are delivered through a custom manifold fitted to a head coil and connected to a pump system that allows precisely timed and measured delivery of liquids. Because this is feasibility-based measure, the outcome is a count of participants who completed this task.