Several studies have begun to determine the time course of events sensing energy availability in rodents. In contrast, there is not a single study that has examined this in humans to date. A better understanding of this energy sensing machinery in humans is of utmost importance to give us new insights into developing new therapies for common diseases such as obesity, diabetes mellitus, cardiovascular diseases and cancer. In these diseases, disturbances in the energy-sensing machinery possibly play a role. To determine the time course of energy sensing events in humans, the investigators will measure the concentration of various hormones in plasma, and biochemical changes in skeletal muscle at sequential time points during starvation in humans. The investigators choose to study the molecular machinery in muscle, since muscle is very sensitive to fuel deprivation.

Inclusion Criteria:

• Healthy males
• Age 19-29 years old
• Body mass index (BMI) 19-25 kg/m2
• Stable weight for the last 3 months
• Caucasian
• Fasting plasma glucose (FPG) < 6 mmol/L
• Well-controlled blood pressure (< 150/95 mmHg)
• Creatinine <100 umol/l
• Hb > 7.5 mmol/l
• Negative family history (first degree) of type 2 diabetes mellitus (DM2)

Exclusion Criteria:

• Use of medication known to affect glucose metabolism (for example prednisone) or lipid metabolism
• Significant (chronic) disease
• Smoking (current)
• Alcohol consumption of more than 14 units per week at present or in the past
• Difficult accessible veins for insertion of an intravenous catheter
• Recent blood donation (within the last 3 months)
• Recent participation in other research projects (within the last 3 months), participation in 2 or more projects in one year
• Rigorous exercise/sports 5 or more days a week