The stomach's response to unappetizing food: cephalic-vagal effects on gastric myoelectric activity

The aim of this investigation was to determine the effects of sham feeding food that was perceived as unappetizing on the cephalic-vagal reflex as mea sured by changes in gastric myoelectric activity. Thirty-eight healthy huma n participants experienced one of two conditions: ii) an appetizing sham fe eding condition in which participants chewed and expectorated two cooked fr ankfurters, and (ii) an unappetizing sham-feeding condition in which partic ipants chewed and expectorated two cold tofu frankfurters. All participants were asked to chew each mouth-full of food 6-7 times and to be very carefu l not to swallow any of the food. Electrogastrograms (EGGs) were recorded f or 10 min prior to, during, and for 15 min after sham feeding. A questionna ire was given to each participant after the procedure as a manipulation che ck and to assess food palatability. Results from the questionnaire showed, as expected, that the cooked frankfurters were significantly more appetizin g than the cold tofu frankfurters (P < 0.01), In the group sham fed appetiz ing food, 3 cycles per minute (cpm) power increased during sham feeding, bu r the change was not significant; however, 3 cpm power decreased in the gro up sham fed unappetizing food. This difference was significant (P < 0.05). In conclusion, we have demonstrated that the cephalic-vagal reflex, as meas ured by power in the 3 cpm frequency region of the EGG, is sensitive to the subjective palatability of the food.