Meal ingestion induces sensations that are influenced by a series of conditioning factors.

Aim: to determine the conditioning effect of previous digestive symptoms to a standardized probe meal.

Controlled randomized parallel study in healthy subjects on the conditioning effect of previous digestive symptoms on the responses to a comfort meal. Digestive symptoms will be induced by lipid (or sham) infusion into the intestine. On three separate days, digestive sensations (satiety, abdominal bloating, digestive well-being, mood, discomfort) in response to a comfort meal will be measured before, during and after the intervention. Primary outcome: effect of conditioning on the sensation of digestive well-being measured by -5 to +5 scale after a comfort meal. Secondary aim: effect of conditioning on abdominal on homeostatic sensations (satiety, fullness, discomfort, nausea).

Participants (16 women, 8 in the intestinal infusion and 8 in the sham intervention) will be instructed to eat a standard dinner the day before, to consume a standard breakfast at home after overnight fast, and to report to the laboratory, where the comfort meal will be administered 4 h after breakfast. Studies will be conducted in a quiet, isolated room. On each study day, participants will be intubated with a nasoduodenal feeding tube under fluoroscopic control for lipids or sham infusion. A comfort meal will be administered and perception of digestive sensations will be measured at 5 min intervals 10 min before and 20 min after ingestion and at 10 min intervals up to 60 min after the probe meal.

Inclusion Criteria:

• non-obese

Exclusion Criteria:

• history of gastrointestinal symptoms
• prior obesity
• use of medications
• history of anosmia and ageusia
• current dieting
• alcohol abuse
• psychological disorders
• eating disorders