This study tests the hypothesis that exercise training can confer additional benefit to patients in weight-loss programs in the form of improvements in either metabolic or vascular parameters or both. Patients will be randomized to either diet plus conventional physical activity or diet plus a planned exercise training. The interventions will be carried out until the patients lose between 5% and 7.5% of their initial weight. At entry and at the end, all subjects will be evaluated for outcomes such as blood glucose, lipid profile, insulin, c-reactive protein, fibrinogen, vascular reactivity (doppler ultrasound) and total and abdominal visceral fat (CT-scan). Both groups will be compared.

Inclusion Criteria:

• BMI> 30 and <40

Exclusion Criteria:

• Diabetes mellitus
• Active endocrine disease
• Active heart disease
• Active smoking
• Medical contra-indications for exercise
• Using anti-obesity drugs