Endogenous vs. Exogenous Ketone Bodies

Impact of Endogenous vs. Exogenous Ketone Bodies on Appetite Control and Macronutrient Oxidation

Aim of the study is to compare the origin of ketone bodies: endogenous ketone bodies due to 36 hours fasting or 24 hours of ketogenic diet vs. exogenous ketone bodies as supplements additional to normal diet.

Secondary aim of the study is to validate the new metabolic chambers.

Each study week starts with a 3-day run-in period with controlled diet at home and ends with a test-meal (breakfast) in the lab and following food record over the rest of the day at home.

1. week: physical activity level (PAL) 1.3, 3 intervention days in the metabolic chamber: ad libitum energy intake, washout day, isocaloric diet, 36 hours fasting
2. week: physical activity level (PAL) 1.3, 2 intervention days in the metabolic chamber: isocaloric diet, 36 hours fasting
3. week: physical activity level (PAL) 1.6, 2 intervention days in the metabolic chamber: ad libitum energy intake, 36 hours fasting
4. week: physical activity level (PAL) 1.6, 2 intervention days in the metabolic chamber: isocaloric diet, ketogenic diet (isocaloric)
5. week: physical activity level (PAL) 1.6, 2 intervention days in the metabolic chamber: isocaloric diet, isocaloric diet + ketone body supplements (isocaloric)

Inclusion Criteria:

• healthy
• BMI 19-29 kg/m2
• low-medium habitual physical activity
• women using hormonal contraceptive

Exclusion Criteria:

• smoking
• chronic illnesses
• food allergies / intolerances
• vegans and vegetarians
• regular high physical activity (exercise >1 hour/d)
• current weight loss diet / weight loss of >5 kg in the last 3 months
• pregnant / lactating women
• persons incapable of giving informed legal consent