Studies of Biological Changes Related to Weight Loss After Gastric Bypass Surgery
Studies of Biological Changes Related to Weight Loss After Gastric Bypass Surgery
Weight loss achieved by dieting induces multiple changes. These changes include a decrease in
 metabolic rate (the rate in which the body burns its calories), an increase in appetite and
 other physiological and hormonal changes that may be the cause of failure in dieting. Many of
 these parameters that have never been evaluated when weight is lost after gastric bypass
 surgery will be tested in this study.
While gastric bypass surgery (GBS) is known to be highly effective in achieving significant
 weight loss, it is also associated with other biologic changes that occur in the body when
 weight is lost. In this study, subjects undergoing gastric bypass surgery will be followed
 throughout the weight loss period. They will undergo four detailed medical evaluations to
 assess changes in several biological systems that occur in the body when weight is lost.

 The initial assessment will be performed before the surgery (testing period 1). After surgery
 is completed, subjects will attend clinic visits at the Rockefeller University outpatient
 clinic. During these visits, weight and leptin levels will be monitored. Two additional
 assessments will be performed during weight loss, when subjects lose 10% and 20% of their
 initial weight (testing periods 2 and 3 respectively). A final evaluation will be performed
 after weight is stabilized, about 18 months after the surgery is completed (testing period
 4). Each testing period will be performed over a 2 week period in an inpatient setting at the
 Rockefeller University Hospital. During testing periods subjects will undergo a series of
 metabolic, behavioral, hormonal, immune and molecular tests to evaluate changes that occur in
 the body after weight loss. Subjects will receive monetary compensation for participating in
 the study.
Inclusion Criteria:

 -  18 - 65 years old

 -  Subjects approved for gastric bypass surgery

 Exclusion Criteria:

 -  Subjects not approved for gastric bypass surgery