Prolonged latency of the gustatory evoked potentials for sucrose solution in subjects living with obesity compared with normal-weight subjects.

Objectives: A difference in cortical treatment of taste information could alter food intake promoting the development of obesity. The main purpose was to compare, in subjects living with obesity (OB) and normal-weight subjects (NW), the characteristics of gustatory evoked potentials (GEP) for sucrose solution (10 g.100 mL^-1) before and after a standard lunch. The secondary objective was to evaluate the correlations between GEP and the plasmatic levels of acylated ghrelin, leptin, insulin and serotonin.

Methods: Each subject had 2 randomized sessions spaced by an interval of 2 days. During one session, subjects were fasting and during the other, subjects took a lunch low in sugar. In each session, subjects had a blood test before a first GEP recording followed by a second GEP recording either after a lunch (feeding session) or no lunch (fasting session).

Results: Twenty-eight OB (BMI: 38.6 ± 9.0 kg.m^-2) were matched to 22 NW (BMI: 22.3 ± 2.2 kg.m^-2). GEP latencies were prolonged in OB regardless the sessions and the time before and after lunch, compared with NW (in Cz at the morning: 170 ± 33 ms vs 138 ± 25 ms respectively; p < 0.001). The increase in latency observed in NW after lunch was not observed in OB. Negative or positive correlations were noted in all participants between GEP latencies and ghrelin, leptin, insulin plasmatic levels (P1Cz, r = -0.38, r = 0.33, r = 0.37 respectively, p < 0.0001).

Conclusions: This study highlights a slower activation in the taste cortex in OB compared with NW.