Effects of Acute Aerobic Exercise and Protein Intake on Appetite and the Neural Response to Visual Food Cues

Abstract

Functional magnetic resonance imaging (fMRI) studies reveal altered food cue processing in brain reward centers [e.g. insula (INS), amygdala (AMY), orbitofrontal cortex (OFC), caudate (CAU), putamen (PUT)] of obese vs. normal weight individuals. We assessed the effects of acute aerobic exercise (Ex) and protein intake [normal (NP) or high (HP)] on appetite and the neural response to visual food cues (NRVFC) in 7 women (BMI 35.5 ± 1.0 kg/m2, 29 ± 3 y). All meals for 24h were provided, dinner was NP or HP (15 vs. 30% of energy), and subjects rested (R) or Ex for 30min before dinner, resulting in 4 testing days (NPR, NPEx, HPR, HPEx) with 4 fMRI per day (pre, 1, 2.5, and 4h after dinner). Regions of interest were defined by activation clusters (threshold p< 0.001) from the first fMRI scan and where activation peaks fell within left/right INS, AMY, OFC, CAU, and PUT. Appetite was assessed before and after fMRI, Ex/R, and dinner. Hunger and desire to eat decreased and fullness increased at all postprandial time points vs. pre-dinner with no difference among testing days. NRVFC was not different among time points or testing days. Data from this pilot study do not support an effect of acute exercise and protein intake on neural food cue processing in obese women, but interpretations should be made with caution due to the small sample size. Support: NIH UL1 TR001108, USDA 2011-38420-20038