Decision-making and Food Intake

Decision-making and Food Intake ("Buffet Study")

The study will investigate how the expectation of food availability impacts the response to food cues, mood, interoceptive awareness, and consumption of food intake in healthy, naturally cycling women.

In this within-subjects, randomized crossover study, we will probe how perceived meal availability shapes eating behavior, cognition, and metabolic markers in healthy, naturally cycling women. Each woman attends two appointments in the afternoon (starting at 12 pm after an overnight fast): one in which meal timing and duration are fully disclosed ("certain" condition) and one in which that information is intentionally withheld ("uncertain" condition). During each appointment, participants first undergo a set of cognitive and behavioral tests, then are invited to sample ad libitum from a 30-item buffet under the respective certainty or uncertainty instructions. Venous blood is collected at six fixed intervals to measure fluctuations in ghrelin, leptin, insulin, glucose, and cortisol. To capture real-world eating patterns, participants also log all intake in a smartphone food-tracking app for three days leading up to the initial session.

Inclusion Criteria:

• Nulliparous women (age: 18-35 years) with a regular menstrual cycle (25-32 days)
• Legally competent/Consent to participate
• Language proficiency in German (native speaker, fluent)
• Physically and mentally healthy
• Body mass index (BMI) of 18.5 - 30 kg/m2

Exclusion Criteria:

• Current or use of hormonal contraceptives in the previous 6 months

• Current use of hormonal intra-uterine devices (IUDs)

• Previous or current pregnancy

• Diagnosed psychological or metabolic disorder

• Former or current illnesses of:

  1. Brain or mind (including anxiety disorders, depression, eating disorders, personality disorders, alcohol, drugs or drug or non-substance dependence, neurological disorders other than occasional headache, psychiatric or neurological abnomalities)
  2. Heart or blood circulation/cardiovascular disease (myocardial infarction, stroke, hypertension, hypotension, having a pacemaker)
  3. Gastro-intestinal disorders (e.g. colon diseases, irritable bowel syndrome, Crohn's disease)
  4. Endocrine disorders (e.g. thyroid disorders)
  5. Other serious past or present medical conditions (for example, metabolic syndrome, diabetes)

• Other serious health problems or current severe mental or physical stress.

• Blood clotting disorder

• Fear of drawing blood

• Severe anemia

• Previously diagnosed hypoglycemia episodes

• Regular intake of medication (e.g. Antidepressant/anti-anxiety medication)

• Blood donation within 4 weeks before the study appointment

• Intake of anticoagulant medications

• illegal drug consumption

• smoking or nicotine consumption

• extreme athletes

• vegetarians or vegans or any other dietary restrictions due to allergies or intolerances

• shift workers