Digestive, cognitive and hedonic responses to a meal

Background: Gut dysfunctions may be associated to digestive symptoms. We hypothesized that the gut can also originate pleasant sensations, and wished to demonstrate the hedonic component of the digestive response to a meal.

Methods: Healthy subjects (n = 42) were evaluated during basal fasting conditions and during experimentally induced fullness sensation (either by gastric distension or duodenal nutrient infusion). In each set of studies, a 240 mL test meal (12 kcal broth) and water, as inert control meal, were administered on separate days in a randomized, cross-over design. Gastric accommodation, the cognitive response and the hedonic dimension (both by 10 score scales) were measured 9 min before and 60 min after the meal.

Key results: In basal conditions, the test meal induced a significantly greater gastric relaxation than the control meal (166 ± 28 mL isotonic volume increase 67 ± 14 mL; p = 0.002). Both meals induced epigastric fullness (3.8 ± 0.7 score and 3.2 ± 0.8 score, respectively; p = 0.740), but contrary to the inert meal, with the active meal this conscious sensation had a pleasant dimension (digestive comfort increase by 1.3 ± 0.6 score with active meal vs -1.1 ± 0.6 decrease with inert meal; p = 0.015). Experimentally induced fullness was associated to a decrease in digestive well-being or abdominal discomfort, which improved only after the active meal but not the inert meal.

Conclusions & inferences: When appropriate conditions are met, the response to a meal includes a hedonic dimension involving pleasant sensation of digestive well-being.