 Clinical trial comparing two health education programs for obese patients in order to achieve a substantial and beneficial weight loss, using mediterranean diet. Patients will be allocated to two groups, one will receive education in diet and lifestyle, and the other one the same plus cooking lessons. The intervention period is for 6 months with monthly visits and phone and email contacts in between. An extension observation period of two years is also planned with 6 months contacts in our clinic, also with phone and email contact available. 