The Effects of Exenatide (Byetta ) on Energy Expenditure and Weight Loss in Nondiabetic Obese Subjects

Obesity can lead to a number of health problems including diabetes, heart disease, stroke, low back pain, fatty liver disease, and osteoarthritis. The medical treatments currently available for obesity are limited. Exenatide is an injectable medication approved for treatment of type 2 diabetes that causes weight loss in some diabetic subjects. The reasons exenatide is thought to cause weight loss include decreased food intake, increased feelings of fullness and nausea. Because levels of a human gut hormone (glucagon like peptide 1) that is similar to exenatide have been shown to be related to resting energy expenditure, it is also possible that exenatide may have effects on a person s metabolism, a.k.a. energy expenditure, but any effect of exenatide on energy expenditure has yet to be evaluated. Even though exenatide is used to treat diabetes, administration of exenatide to non-diabetic lean individuals did not cause frankly low blood sugars. The primary goal of this study is to investigate the way in which exenatide given twice a day to obese (BMI \>= 30 kg/m\^2) people without diabetes might lead to weight loss. Because response to weight loss treatment can be highly variable between individuals, we will look at the role of exenatide in changing food intake and energy expenditure as possible explanations for weight loss. We will also assess the safety profile of exenatide in non-diabetic obese people. This study will involve the use of exenatide or placebo, determined randomly, in obese individuals without diabetes over a 5 week period. The primary measurements will include effects of exenatide on energy expenditure and food intake. We will also look at changes in body fat and the levels of hormones involved in the sensations of hunger and fullness. We will assess if any exenatide-induced changes can predict which individuals lose weight over the 5 weeks. The safety and side effects of exenatide in non-diabetic individuals during this time will also be determined. Findings from this study would help to determine how exenatide works to cause weight loss in people without diabetes, who might benefit most, and would help to improve understanding of why some people respond better to weight loss treatment than others.