An interventional study of Perceived food uncertainty and Perceived food certainty in Behavior, Hormones and Stress, sponsored by German Institute of Human Nutrition. Recruiting at 1 site in Germany. Open to female participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-08-21.
Sponsored by German Institute of Human Nutrition · Not applicable, Interventional, and Basic science
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.
Exclusion Criteria:
Former or current illnesses of:
Behavioral: Perceived food uncertainty
Behavioral: Perceived food certainty
Participants remain unaware of both the scheduled time and the length of the next meal.
Participants are aware of both the scheduled time and the length of the next meal.
Laboratory food intake
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Food-specific inhibitory control
Food-specific inhibitory control measured by a go/no-go task adapted from Teslovich et al., 2014.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Risk propensity on a decision-making task
In this task, participants decide between a risky/gamble or safe option, based on a paradigm by Liu et al., 2021.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Delay Discounting behavior in a computerized task
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Range adaptation in reinforcement learning
Range adaptation in the context of a reinforcement learning task is assessed using a paradigm described by Gueguen et al., 2024.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Behavioral economic paradigm
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Heart rate
Resting-state and task-based heart rate, measured with a three-point electrocardiogram (ECG)
Time frame: On 1st and 2nd visit (after approximately 30 days)
Heart-rate variability
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Electrodermal activity
Resting-state and task-based skin conductance measured with two electrodermal activity electrodes placed on the fingers of the non-dominant hand.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Subjective stress levels
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Subjective hunger levels
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Subjective fullness levels
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Subjective satiety levels
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Subjective food cravings
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Levels of diverse hormones
Levels of different hormones (e.g., estradiol, progesteron, testosterone, ghrelin, leptin) will be measured via blood sampling.
Time frame: On 1st and 2nd visit (approximately 30 days later)
Levels of cortisol
Cortosol levels will be assessed multiple times throughout the visit as an objective measure of stress.
Time frame: On 1st and 2nd visit (approximately 30 day later)
Insulin levels
Levels of insulin will be measured multiple times throughout the visit via blood sampling.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Glucose levels
Glucose levels will be measured multiple times throughout the visit via blood sampling.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Stress eating
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Reward-related behavioral activation and inhibition
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Impulsivity
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Mood
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Emotion regulation
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Perceived stress
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
State anxiety
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Interoceptive awareness
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.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Loss of control over eating
Participants will rate their subjective loss of control over eating during the ad lib buffet task. Higher values indicate greater loss of control.
Time frame: on 1st and 2nd visit (after approximately 30 days)
Habitual food intake
Self-reported habitual food intake (i.e., all food and drinks consumed) is assessed via an app and/or through additional handwritten food diaries on three consecutive days.
Time frame: On three days before the 1st visit
Quantification of epigenetic markers related to appetite, menstrual cycle, and stress
Epigenetic markers associated with appetite regulation, menstrual function, and stress response will be measured in blood samples. Site-specific epigenetic modifications (e.g., DNA methylation or histone modifications) will be quantified using validated molecular assays.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Depressive mood
Depressive mood is assessed using the German version of the Beck Depression Inventory (BDI; Kühner et al., 2007). The questionnaire measures the severity of depressive symptoms experienced over the past two weeks. Higher total scores indicate more pronounced depressive symptomatology.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Body image
Body image is assessed using the Body Shape Questionnaire (BSQ; Pook et al., 2008), which measures concerns related to body shape commonly associated with eating disorders. Participants rate how frequently they experience body-related thoughts and feelings. Higher scores indicate greater body shape concern.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Trait food cravings
Food cravings are measured using the trait version of the Food Cravings Questionnaire (FCQ-T; Meule et al., 2012). Responses are given on a six-point scale from "never/not applicable" to "always," with higher scores indicating more frequent and intense cravings.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Dietary patterns
Dietary patterns are assessed using a food frequency questionnaire (Haftenberger et al., 2018), which captures the frequency and quantity of consumption across various foods and food groups over the past month. Participants indicate how often they consumed specific items and in which quantity, allowing for an overview of habitual dietary intake and eating patterns.
Time frame: Day 2 (after approximately 30 days after day 1 i.e., 1st visit)
Intuitive eating
Intuitive eating is assessed using the Intuitive Eating Scale-2 (van Dyck et al., 2019), which evaluates individuals' tendency to rely on physical hunger and satiety cues to guide decisions about when, what, and how much to eat. Participants respond on a five-point scale ranging from "strongly disagree" to "strongly agree." Higher scores reflect a greater inclination toward intuitive eating behaviors.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Food insecurity status
Food insecurity status is assessed using the Food Insecurity Experience Scale (FIES; Depa et al., 2018), which evaluates individuals' access to food by addressing factors such as financial constraints, availability, and dietary quality. Response options include "yes," "no," "refused," and "don't know." Higher scores reflect greater severity of food insecurity.
Time frame: On 1st and 2nd visit (after approximately 30 days)
Restrained eating
Restrained eating is assessed using the "Cognitive Restraint of Eating" subscale from the Three-Factor Eating Questionnaire (TFEQ; Pudel \& Westenhöfer, 1989). The subscale includes both true/false items and statements rated on a four-point Likert scale ranging from 1 ("always") to 4 ("never"). Higher total scores indicate greater cognitive restraint in eating behavior.
Time frame: Day 1 (1st visit out of 2)
Eating motives
Eating motives will be assessed using the Eating Motives Survey (TEMS; Renner et al., 2012). Items are rated on a 7-point Likert scale, ranging from "never" to "always". Higher scores on TEMS subscales indicate a greater reliance on those eating motives when making food or eating choices.
Time frame: Day 1 (1st visit out of 2)
Family climate
Family climate is measured using the Familien Klima Skale (FKS; Roth, 2003). Items are rated on a 5-point Likert scale ranging from 1) "does not apply at all," 2) "applies little," 3) "applies moderately," 4) "applies predominantly," to 5) "applies almost completely." Higher total scores indicate a better family climate.
Time frame: Day 1 (1st visit out of 2)
Attachment styles
Attachment styles will be assessed using the Adult Attachment Scale (AAS; Schmidt et al., 2004). Items are rated on a five-point Likert scale ranging from "not at all true" to "exactly true." Higher scores on each subscale indicate a stronger endorsement of the corresponding attachment dimension. The subscales/attachment styles assessed are secure, avidant, anxious.
Time frame: Day 1 (1st visit out of 2)
Gut Microbiome
To assess the relationship between the gut microbiome and participants' food intake during the ad libitum meal, fecal samples will be collected prior to the first visit, during the observational phase in which participants record their habitual dietary intake.
Time frame: 1 to three days before the 1st visit
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German Institute of Human Nutrition