How sweet taste perception promotes excess caloric intake, obesity and diabetes is debated. There is little evidence for altered sweet taste in obesity, and adiposity does not predict sweet liking. However, overweight and obese subjects generally prefer high fat, sweet stimuli. The effect of adiposity on brain responses to sweet taste has not been systematically assessed, particularly in adults. In this ongoing study, 8 normal weight women (BMI 23.4±2.2 kg/m2, age 47±14 y) and 7 women with obesity (BMI 48.8±9.2 kg/m2, age 44±10 y), underwent functional magnetic resonance imaging (fMRI) on a Siemens 3T Magnetom Prisma using 32-channel head coil. fMRI assessed brain responses to 0.40M and 0.10M sucrose sprayed onto the tongue as compared to water (7 sucrose and 17 water trials in each 5:52 min long scan). Two scans were acquired at each concentration, where 0.40M and 0.10M scans alternated and the first scan sucrose concentration was counterbalanced across subjects. Across the whole sample, BOLD activation from [Sucrose (0.40M) > water] was detected (p<0.01, k>10) in gustatory insula, sensorimotor cortex/rolandic operculum, right ventral striatum, and bilateral posterolateral orbital cortex (the latter only in [Sucrose (0.10M) > water]). After including BMI as a covariate, a positive association of BMI and [Sucrose (0.40M) > water] contrast was present in the left gustatory insula area (peak, p<0.005), right rolandic operculum and sensorimotor cortex (ps<0.008). There were no negative correlations between BMI and the [Sucrose (0.40M) > water] contrast. BMI did not correlate with the [Sucrose (0.10M) > water] contrast. These preliminary findings suggest that women with obesity have greater responses in gustatory cortex to sweet taste compared to lean women. This is consistent with reports that overweight and obese subjects generally prefer sweet foods. The data might also suggest that gustatory cortex reactivity is altered by excess adiposity, possibly complicating diet compliance.
R.V. Considine: None. S.S. Janetsian-Fritz: None. M.D. Picklesimer: None. S.E. Wainscott: None. M. Dzemidzic: None. D.A. Kareken: None.
American Diabetes Association (1-18-ICTS-036 to R.V.C.)