Bed Rest, Alternate Daily Fasting and Incretin Effect

Rigshospitalet, Denmark20 enrolled

Overview

Bed rest produces insulin resistance in healthy volunteers. In this study the investigators aim to investigate the effect of 8 days bed rest on the incretin effect and how alternate daily fasting affects cognitive function and the insulin resistance produced by bed rest. The subjects will be randomized to either 3 meals a day (isocaloric diet), alternate daily fasting or one meal/day every second day (25% of daily calorie need) and four meals/day every second (175% of daily calorie need). The investigators hypothesize: 1. Bed rest reduces the incretin effect 2. Alternate daily fasting improves the cognitive function (memory and concentration) compared to isocaloric diet 3. Alternate daily fasting reduces insulin resistance produced by bed rest compared to isocaloric diet

All subjects will undergo 8 days of bedrest. Outcome measures will be performed before, under and immediately after the bed rest period. The individual study period will be 10 days in total.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Metabolic Syndrome Type 2 Diabetes Critical Illness

Interventions

Bed restOTHER

8 days of full bed rest

OGTTOTHER

Oral glucose tolerance test with 75 g of glucose before and after bed rest

IVGTTOTHER

Intravenous glucose tolerance test mimicking the glucose profile from the corresponding OGTT

Cognitive testingOTHER

Daily testing of memory and concentration using standardized tests

Muscle and fat biopsiesOTHER

Biopsies will be obtained before and after bed rest

Dual-energy X-ray Absorptiometry (DXA) scanOTHER

DXA scan to evaluate fat and muscle distribution before and after bed rest

MRIOTHER

Functional MRI to evaluate cognitive function and abdominal MRI to evaluate visceral fat before and after bed rest

Eligibility

Sex: MALEMin age: 18 YearsMax age: 35 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * BMI\<25kg/m2 * VO2 max normal for age Exclusion Criteria: * Tobacco smoking * Alcohol ingestion \> 14 units per week * Diabetes in nearby relatives * Resection of the small intestine * History of gastric bypass surgery * Risk of deep venous thrombosis * Female

Outcomes

Primary Outcomes

Incretin effect

Measured by Insulin levels during Oral glucose tolerance test (OGTT) and Intravenous glucose tolerance test (IVGTT)

Time frame: 24 weeks

Cognitive function

Evaluated by cognitive testing and functional Magnetic Resonance imaging (MRI)

Time frame: 18 months

Insulin resistance

Evaluated by insulin resistance indexes, HOMA-IR and Matsuda index

Time frame: 12 weeks