# NCT07133529: Decision-making and Food Intake ("Buffet Study")

Registry record: https://clinicaltrials.gov/study/NCT07133529 (retrieved 2026-09-30). Sponsor: German Institute of Human Nutrition.

## What you are forecasting

**Primary hypothesis (implied by design (title and first listed primary outcome)):** Participants eat more at the laboratory ad libitum buffet in the perceived food-uncertainty condition than in the perceived food-certainty condition.

**Resolution rule:** Supported if food intake (energy or grams, whichever the report uses) is significantly higher under perceived uncertainty than under perceived certainty. The registry lists 28 primary outcomes; only buffet intake decides this forecast.

**Alpha:** 0.05, two-sided, unless the report states otherwise

**Effect metric for your 90% interval:** Cohen's d (within-subject, crossover) for uncertainty minus certainty in buffet intake (positive = more eaten under uncertainty).

**Moderator to consider:** Do stress eaters (Salzburg Stress Eating Scale), or participants with higher stress or cortisol responses, eat more under uncertainty?

## Design

- Allocation: RANDOMIZED; model: CROSSOVER; purpose: BASIC_SCIENCE
- Masking: SINGLE ['PARTICIPANT']
- Enrollment: 45 (estimated)
- Phase: NA
- Status on registry: RECRUITING; start 2025-08-04; primary completion 2026-07-31 (estimated)

## Arms

- **Perceived food uncertainty** (experimental): (no description on registry)
- **Perceived food certainty** (experimental): (no description on registry)

## Primary outcome(s) as registered

- **Laboratory food intake** (On 1st and 2nd visit (after approximately 30 days)): Food consumed during a laboratory ad libitum buffet task, in which participants are able to order and consume different foods from a menu of their own liking.
- **Food-specific inhibitory control** (On 1st and 2nd visit (after approximately 30 days)): Food-specific inhibitory control measured by a go/no-go task adapted from Teslovich et al., 2014.
- **Risk propensity on a decision-making task** (On 1st and 2nd visit (after approximately 30 days)): In this task, participants decide between a risky/gamble or safe option, based on a paradigm by Liu et al., 2021.
- **Delay Discounting behavior in a computerized task** (On 1st and 2nd visit (after approximately 30 days)): In this task, participants are asked to choose between an immediate and delayed monetary reward, based on a task paradigm by Eisenstein et al., 2015.
- **Range adaptation in reinforcement learning** (On 1st and 2nd visit (after approximately 30 days)): Range adaptation in the context of a reinforcement learning task is assessed using a paradigm described by Gueguen et al., 2024.
- **Behavioral economic paradigm** (On 1st and 2nd visit (after approximately 30 days)): In this task, participants manage a shared resource by deciding how much to extract from a common pool over multiple rounds. Based on their individual extraction, participants receive a monetary reward, which is reduced once the group exceeds a predefined extraction limit. Adapted from Lagenbach et al., 2019.
- **Heart rate** (On 1st and 2nd visit (after approximately 30 days)): Resting-state and task-based heart rate, measured with a three-point electrocardiogram (ECG)
- **Heart-rate variability** (On 1st and 2nd visit (after approximately 30 days)): Resting-state and task-based heart-rate variability measured with a three-point electrocardiogram (ECG). Respiratory activity will also be recorded using a breathing belt to correct for breathing-related artifacts.
- **Electrodermal activity** (On 1st and 2nd visit (after approximately 30 days)): Resting-state and task-based skin conductance measured with two electrodermal activity electrodes placed on the fingers of the non-dominant hand.
- **Subjective stress levels** (On 1st and 2nd visit (after approximately 30 days)): Subjective stress levels are measured on a semi-continous scale from 1 (not at all) to 100 (extremely) repeatedly during each visit to assess stress responses to perceived food availability. Higher scores indicate greater stress.
- **Subjective hunger levels** (On 1st and 2nd visit (after approximately 30 days)): Subjective hunger levels are measured on a semi-continous scale from 1 (not at all) to 100 (extremely) repeatedly during each visit to assess changes in subjective hunger ratings in response to perceived food availability. Higher scores indicate greater hunger.
- **Subjective fullness levels** (On 1st and 2nd visit (after approximately 30 days)): Subjective fullness levels are measured on a semi-continous scale from 1 (not at all) to 100 (extremely) repeatedly during each visit to assess changes in subjective fullness ratings in response to perceived food availability. Higher scores indicate greater fullness.
- **Subjective satiety levels** (On 1st and 2nd visit (after approximately 30 days)): Subjective satiety levels are measured on a semi-continous scale from 1 (not at all) to 100 (extremely) repeatedly during each visit to assess changes in subjective satiety ratings in response to perceived food availability. Higher scores indicate greater satiation.
- **Subjective food cravings** (On 1st and 2nd visit (after approximately 30 days)): Subjective cravings for sweet, salty, and fatty foods are measured on a semi-continous scale from 1 (not at all) to 100 (extremely) repeatedly during each visit to assess changes in subjective food craving ratings in response to perceived food availability. Higher scores indicate stronger food craving.
- **Levels of diverse hormones** (On 1st and 2nd visit (approximately 30 days later)): Levels of different hormones (e.g., estradiol, progesteron, testosterone, ghrelin, leptin) will be measured via blood sampling.
- **Levels of cortisol** (On 1st and 2nd visit (approximately 30 day later)): Cortosol levels will be assessed multiple times throughout the visit as an objective measure of stress.
- **Insulin levels** (On 1st and 2nd visit (after approximately 30 days)): Levels of insulin will be measured multiple times throughout the visit via blood sampling.
- **Glucose levels** (On 1st and 2nd visit (after approximately 30 days)): Glucose levels will be measured multiple times throughout the visit via blood sampling.
- **Stress eating** (On 1st and 2nd visit (after approximately 30 days)): Changes in food intake related to stress is assessed with the Salzburg Stress Eating Scale (SSES; Meule et al., 2018). Higher Scores indicate increased food intake in response to stress, while lower scores indicate reduced food intake when experiencing stress.
- **Reward-related behavioral activation and inhibition** (On 1st and 2nd visit (after approximately 30 days)): Reward-related behavioral activation and inhibition are assessed using the Behavioral Inhibition System/Behavioral Activation System questionnaire (BIS/BAS; Strobel et al., 2001). Participants respond on a four-point Likert scale: "strongly disagree," "disagree," "agree," and "strongly agree." Higher scores on the BIS scale indicate greater behavioral inhibition, while higher scores on the BAS scale reflect stronger behavioral activation.
- **Impulsivity** (On 1st and 2nd visit (after approximately 30 days)): Impulsivity is assessed using the Barratt Impulsiveness Scale (BIS; Meule et al., 2011). Participants respond using a four-point scale: "rarely," "occasionally," "often," and "almost always." Higher scores indicate greater impulsivity.
- **Mood** (On 1st and 2nd visit (after approximately 30 days)): Mood is measured twice during each visit before and after the ad libitum meal using the Positive and Negative Affect Schedule (PANAS; Janke \& Glöckner-Rist, 2014). Participants respond to 20 mood adjectives-10 reflecting positive affect and 10 reflecting negative affect-using a five-point scale: "not at all," "very slightly," "moderately," "quite a bit," and "extremely." Higher scores on the positive affect scale indicate stronger positive mood, while higher scores on the negative affect scale indicate stronger negative mood.
- **Emotion regulation** (On 1st and 2nd visit (after approximately 30 days)): Emotion regulation is assessed using the Emotion Regulation Questionnaire (ERQ; Abler \& Kessler, 2009), which captures individual differences in the use of two distinct strategies to regulate emotions (cognitive reappraisal and expressive suppression). Participants rate their agreement with each item on a seven-point Likert scale, ranging from "strongly disagree" to "strongly agree." Higher scores on each subscale indicate more frequent use of the corresponding regulation strategy.
- **Perceived stress** (On 1st and 2nd visit (after approximately 30 days)): Perceived stress is assessed using the Perceived Stress Scale (PSS-10; Schneider et al., 2020), which aptures the extent to which individuals perceive their lives as unpredictable, uncontrollable, and overwhelming over the past month. Participants respond to general statements using a five-point scale ranging from "never" to "very often." Higher scores indicate greater perceived stress.
- **State anxiety** (On 1st and 2nd visit (after approximately 30 days)): State anxiety is assessed twice during each visit before and after the ad lib meal using the state version of the State-Trait Anxiety Inventory (STAI; Grimm, 2009); which captures the current intensity of anxiety as experienced at the moment of assessment. Response options include "almost never". "a little", "moderately", and "very much". Higher scores indicate higher levels of state anxiety.
- **Interoceptive awareness** (On 1st and 2nd visit (after approximately 30 days)): Interoceptive awareness is assessed using the Multidimensional Assessment of Interoceptive Awareness (MAIA; Eggart et al., 2021). The questionnaire measures various aspects of the awareness of internal bodily sensations. Participants respond to statements using a six-point scale: "never," "very rarely," "rarely," "occasionally," "frequently," and "always." Higher scores reflect greater awareness of bodily sensations.
- **Loss of control over eating** (on 1st and 2nd visit (after approximately 30 days)): Participants will rate their subjective loss of control over eating during the ad lib buffet task. Higher values indicate greater loss of control.

## Secondary outcomes (names only)

- Habitual food intake (On three days before the 1st visit)
- Quantification of epigenetic markers related to appetite, menstrual cycle, and stress (On 1st and 2nd visit (after approximately 30 days))
- Depressive mood (On 1st and 2nd visit (after approximately 30 days))
- Body image (On 1st and 2nd visit (after approximately 30 days))
- Trait food cravings (On 1st and 2nd visit (after approximately 30 days))
- Dietary patterns (Day 2 (after approximately 30 days after day 1 i.e., 1st visit))
- Intuitive eating (On 1st and 2nd visit (after approximately 30 days))
- Food insecurity status (On 1st and 2nd visit (after approximately 30 days))
- Restrained eating (Day 1 (1st visit out of 2))
- Eating motives (Day 1 (1st visit out of 2))
- Family climate (Day 1 (1st visit out of 2))
- Attachment styles (Day 1 (1st visit out of 2))
- Gut Microbiome (1 to three days before the 1st visit)

## Population

Ages 18 Years to 35 Years; sex: FEMALE; healthy volunteers: True.

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

## Registry summary

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.

## Registry detailed description

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.