Obese patients are going to be submitted to indirect calorimetry pre-operatively and we are going to repeat the same exam 6 months after bariatric surgery (post Roux-en-Y gastric Bypass surgery). They are going to do also body composition analysis in both moments.

The investigators are going to compare the results to see if the bariatric surgery increases their energy expenditure.

Inclusion Criteria:

• obese patients that will be submitted to bariatric procedure

Exclusion Criteria:

• patients that don´t have clinical conditions to be submitted to a bariatric procedure

Obese petiets