There is now a general consensus that the combination of excessive energy intake and a low capacity to oxidize fat will lead to muscular fat accumulation and insulin resistance. It is known for many years that physical exercise is the most powerful treatment to combat insulin resistance, but it is also known that it is difficult to get people to exercise. A major breakthrough has come from the nutrition field, with the finding that resveratrol, a natural polyphenolic compound, could serve as an "exercise mimetic" by protecting mice from many detrimental effects of diet-induced obesity. Therefore the researchers would like to investigate if resVida can increase skeletal muscle mitochondrial function and fat oxidative capacity in obese subjects. The researchers hypothesize that an increased mitochondrial function together with an increased intrinsic activity will lead to a better control of fatty acid handling in muscle, upon a high-fat challenge.

Inclusion Criteria:

• male sex
• age 45-65 years
• body fat percentage > 25%, BMI 30-35 kg/m2
• sedentary
• stable dietary habits
• willingness to abstain from ingestion of resveratrol-containing foods
• healthy

Exclusion Criteria:

• female sex
• unstable body weight (weight gain or loss > 3 kg in the last three months)
• total body fat percentage < 25%
• fasting plasma glucose > 6.1 mmol/l
• hemoglobin < 7.8 mmol/l
• engagement in programmed exercise > 2 hours total per week
• impaired kidney and/ or liver function
• first- or second-degree family member with type 2 diabetes mellitus
• any medical condition requiring treatment and/ or medication use
• intake of dietary supplements except vitamins and minerals
• unwilling to restrict high-resveratrol containing foods
• current alcohol consumption > 20 grams/day
• participation in another biomedical study within 1 month before the screening visit
• a contraindication to MRI scanning. These contraindications include patients with the following devices:
• central nervous system aneurysm clips
• implanted neural stimulator
• implanted cardiac pacemaker or defibrillator
• cochlear implant
• insulin pump
• or metal containing corpora aliena in the eye or brains