The CLOCK Study - A Human Dietary Intervention Study on Peripheral Circadian Clocks and Energy Metabolism

Inclusion Criteria: * BMI between 22 kg/m² and 34,9 kg/m² * Normal glucose tolerance determined in a 75g-oral glucose tolerance test * Impaired fasting glucose determined in a 75g-oral glucose tolerance test * Impaired glucose tolerance determined in a 75g-oral glucose tolerance test Exclusion Criteria: * Shift workers or history of shift work * Men suffering from diseases or conditions that might influence the outcome of the study. Of special interest are diseases that influence body weight regulation (enteropathy, malabsorption, hepatopathy, renal disease, endocrine disorders, diabetes mellitus, eating disorders, heart disease etc.). Also men suffering from coagulopathy, apoplexy and myocardial infarction are excluded from the study. * Men suffering from psychiatric disease * Planned changes in physical activity during the study * Participation in other clinical studies within the last three months * Weight changes \> 2 kg within 2 months prior to screening day * Men unable to give an informed consent * Men unable to engage in the dietary interventions * Men following a special diet