Milk contains a vast number of bioactive components that have been suggested to have a positive impact on human health, of special interest is the effects related to metabolic syndrome and obesity but the effect of the individual milk components is not clear. This study examine whether it is beneficial for overweight and obese children to increase the intake of skim milk, or whey or casein in relation to bodyweight and markers of MS.

The participants will be randomized to receive skim milk, whey milk drink, casein milk drink or mineral water for 3 mo. They will be examined at baseline, end of intervention and followed up 3 month later.

Inclusion Criteria:

• 12 years to 15 years old
• iso BMI larger than 25
• habitual milk intake less than 250 ml/day
• non-smoker
• healthy at the time of inclusion

Exclusion Criteria:

• chronic illnesses
• intake of antibiotic 1 mo before start of intervention