 Methods: It is a multicentric, prospective, comparative study of cohorts. After identification of the eligible subjects, the kinetics production and clearance rates of intestinal and hepatic TRL will be performed in the hospital, using established stable isotope enrichment methodology 5,5,5-D3-L-Leucine, in 2 groups of obese patients 15 patients per surgery procedure, before and 6 months after the surgery. 