Time-restricted Eating and Cognition

This study aims to investigate how time-restricted eating (TRE), more specifically TRE at different times (early vs late in the day), influences brain activity, behavior, decision-making, food intake, physical activity, the gut microbiome and metabolic processes. The study intervention procedure is a replication of that described in Peters et al. (2021).

This study aims to investigate the effects of different time-restricted eating (TRE) interventions on decision-making, brain activity and related processes in an all female cohort over 8 weeks. The study will have a within-subjects, randomised, crossover design, involving two TRE interventions with a comparable feeding and fasting window of 8:16h respectively- early TRE (eating window: 08:00-16:00) and late TRE (eating window: 13:00-21:00). After completing a screening visit, participants will complete a two-week observational phase in which they record their habitual food intake, as well as sleep and physical activity assessment. After this observational phase, participants will be randomly assigned to one of two study arms (early TRE/late TRE or late TRE/early TRE). Here they will complete both TRE interventions for two weeks each, separated by a washout phase of two weeks. During these phases they will record their food intake and physical activity and sleep will be assessed. The participants will be invited for 4 laboratory study visits during this time, at the beginning and end of each TRE intervention.

Eligibility Criteria:
Inclusion Criteria:

* right-handed
* legally competent
* physically and mentally healthy
* BMI: 19-35 kg/m²
* fluent in reading and speaking German

Exclusion Criteria:

* weight change \>5% of body weight during the last 3 months
* pregnancy or breastfeeding
* allergies (inclusion possible after consultation with study doctor)
* history of cardiovascular disease (myocardial infarction, stroke, hypertension, hypotension) in the last year
* severe psychiatric condition, including drug addiction and depression
* impaired renal or liver function
* dementia or other severely debilitating cognitive disease
* history of or current eating disorders (e.g., Bulimia nervosa, Anorexia nervosa, Orthorexia nervosa, Binge-Eating disorder)
* chronic diseases (e.g., Morbus Crohn, Colitis Ulcerosa)
* metabolic disorders (e.g., metabolic syndrome, diabetes type 1 or 2)
* hormonal imbalances (e.g., thyroid gland diseases)
* consuming diseases (e.g., cancer, kachexie) in the last 2 years
* surgical removal (partial removal) of the digestive organs (e.g., gastrectomy) or history of bariatric surgery
* Autoimmune conditions or current infection
* Blood clotting disorders (e.g., haemophilia)
* Severe anemia
* severe claustrophobia
* blood donation four weeks prior to study entry
* glucocorticoid therapy (oral)
* anticoagulant medication (inclusion possible if medication can be paused)
* taking medications that require regular eating
* any medications or supplements known to affect sleep, circadian rhythms, immune activity or metabolism
* taking weight loss, lipid or glucose-lowering medications (any medications that affects metabolism) i.e. metformin
* pacemaker or other electrical implant
* vaccination during the study course or in the two weeks' prior
* immunosuppressive premedication
* currently on a diet/fasting regime (or within 1 month)
* professional athletes
* nicotine consumption
* drug abuse
* alcohol consumption per week more than 14 beers (0,3l)/ wine (0,125l)/ sparkling wine (0,1l)/Schnaps (4cl)
* shift work
* poor sleep quality (PSQI score \> 10 at medical screening)
* travel across more than one time zone one month before study or during study period
* non-removable metallic implants
* fear of blood draw