There is increasing evidence that skeletal muscle lipid content (IntraMyoCellular Lipid, IMCL) markedly increases the risk of metabolic complications, including insulin resistance and cardiovascular events. The investigator hypothesizes that skeletal muscle is passively taking up FFAs when the availability is high, thereby leading to an increased storage. To test this hypothesis, the investigator wants to manipulate FFA levels, by means of exercise, and monitor intramuscular lipid content.

Therefore the objective is to examine the effect of an exercise-induced elevation of FFA on skeletal muscle lipid content in healthy lean men. To this end, skeletal muscle lipid content will be investigated at baseline and after an exercise protocol and again after a four-hour recovery period from exercise, once in a condition with high FFA concentration, once with low FFA concentration. To achieve high- versus low FFA concentrations, an exercise protocol was chosen and participants had to perform this protocol once with a glucose supplementation and once without.

Skeletal muscle lipid content will be determined before, directly after exercise and 4 h post exercise (from muscle biopsies) with or without glucose supplementation.

Inclusion Criteria:

• Male sex
• Age 18-30 years
• Lean, BMI 18-25 kg/m2
• Healthy
• Stable dietary habits
• No medication use

Exclusion Criteria:

• Female sex
• Engagement in programmed exercise > 2 hours total per week
• Cardiac problems, such as angina pectoris, cardiac infarction and arrhythmias
• First degree relatives with type 2 diabetes mellitus
• Any medical condition requiring treatment and/or medication use
• Unstable body weight (weight gain or loss > 3 kg in the past three months)
• Participation in other biomedical study within 1 month prior to the screening visit
• Subjetcs, who do not want to be informed about unexpected medical findings, or do not wish that their treating physician is informed, cannot participate in the study