The prevalence of obesity is growing in elderly with heavy consequences in term of medical complications and mortality, so that this is nowadays an important public health issue.

The major therapeutic solution is dietary restrictions, but and the advantages and the metabolic consequences are not well known in elderly. The MONA study main aim is to assess the metabolic changes in this population, after dietary restrictions, compared to young people.

Primary endpoint : Study the metabolic adaptations of the subcutaneous adipose tissue after a diet in elderly obese men compared to young obese men.

Secondary endpoints : Study the metabolic adaptations of skeletal muscle, the genetic adaptations of subcutaneous adipose tissue and skeletal muscle, the inflammatory and fibrosis modifications of subcutaneous adipose tissue, the insulinosensibility modifications, the modifications on the physical composition, modifications of the energy expenditure in resting state and the oxidation of the substrata, study the lipoproteins metabolism and identify new biomarkers. All those endpoints are studied comparing elderly obese subjects versus young obese subjects.

Inclusion Criteria:

• 30 < years old < 40 OR 60 < years old < 70
• obesity : 30 < BMI < 40
• stable blood pressure (diastolic <90mmHg, systolic < 140mmHg)
• glycemia < 1,26g/L, LDL cholest <1,9-1,6g/L, Triglycerides <2,5g/L
• risk factors concerning high blood pressure, diabetes and dyslipidemia under control

Exclusion Criteria:

• Insulin dependent diabetes, non-insulin dependent diabetes
• high blood pressure
• dyslipidemia
• history of cardiovascular diseases or bariatric surgery
• undernutrition
• HbA1C >7%
• non authorized treatments : Glucagon-like peptide-1 agonists,
• incapacity to do physical activity