Aim of the study is to investigate the impact of meal skipping (breakfast or dinner skipping) on the regulation of glucose metabolism and macronutrient balance (protein/fat/carbohydrate intake vs. -oxidation). An isoenergetic diet with 3 conventional meals (breakfast, lunch, dinner) serves as a control.

The duration of the study is 7 days including 3 days with controlled diet and 4 days (including 5 nights) in a metabolic chamber at the Institute of Nutritional Medicine at the University of Hohenheim.

The study phase in the metabolic chamber consists of (i) 1 day with 3 meals/day = baseline day, (ii) 1 day with breakfast skipping, (iii) 1 day with dinner skipping, (iv) 1 washout day where the subjects leave the chamber between 7 a.m. until 7 p.m..

Beginning on the 3rd study day macronutrient and energy intake as well as the fasting periods are kept constant. To achieve comparable conditions the washout day is setted before the baseline day.

Inclusion Criteria:

• healthy
• not obese (BMI<30)

Exclusion Criteria:

• food allergy
• smoking
• alternative nutrition habits
• chronic disease
• regular medication intake
• claustrophobia