Can Fast-Acting proteins protect muscle after Weight-Loss surgery?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: \- Males and females. * Age between 18 to 60 years. * Body mass index: BMI\> 40 kg/m2, * Biological Review considered satisfactory by the investigator based on the topics covered * Serology HIV ( Human Immunodeficiency Virus )and HCV (Hepatitis C Virus ) negative. * Subject giving his written informed consent * Affiliated to National Health Insurance Exclusion Criteria: * Subject under 18 or over 60 years. * Balance Organic considered abnormal by the investigator. * Serology HIV or HCV positive. * Pregnant or lactating. * For women of childbearing age: β-HCG assay positive and not having reliable contraceptives (oral contraceptive, IUD (Intrauterine Device), implant or hormone patch, abstinence). * Medical or surgical history (judged by investigator to be incompatible with the study). * Subject with unstable psychiatric condition * Blood donation in the two months preceding the study. * Heavy alcohol consumption (\> 2 to 3 glasses per day depending on sex) or presence of an addiction. * Tobacco significant (\> 5 cigarettes / day or equivalent in cigars or pipe tobacco). * Subjects with an allergy or intolerance to dairy products. * Intense sporting activity (\> 5 hours / week). * Being in exclusion on the National Volonteers Data file or having perceived more than 4500 Euros in the year for clinical study participation. * No one under guardianship or not subject to social security. * Subjects deprived of their liberty by judicial or administrative decision. * Refusal to sign the information sheet and written consent for participation * Subject with a cardiovascular or neoplasic evolutive disease * Subject with a severe infection in the 3 months period before inclusion (assessed by doctor during inclusion consultation) * Hypercorticism and dysthyroïdism * Subject with a known neuro-muscular disease * Subject with a chronic or acute inflammatory disease in the 3 months period before inclusion * Subject treated by: corticoids, immunosupressor, anabolic agents, growth factor or having stopped treatment for less than 3 months before inclusion. Furthermore for subjects having undergone a by-pass at Lyon: * Subject consuming pre or probiotics many times per day, having an impact on intestinal flora. * Subject with antibiotics during the 3 months before the beginning of the study. * Subject with an intolerance to dairy products and refusing to consume dairy prod