The Effects of Obesity and Protein Intake on the Kidney

The purpose of this study is to test the hypothesis that being obese leads to changes in kidney function that are independent of, and enhanced by, high dietary protein intake. Kidney function will be measured by the kidney's ability to filter blood and by the amount of protein in the urine. The hypothesis will be tested in the following manner: The first part of the study will involve a crossover design comparing kidney function in obese people with stable weights on a low and high protein diet ("Low/High Protein Study"). The second part of the study will compare kidney function in obese people before and after weight reduction surgery ("Before/After Surgery Study"). Since certain changes in kidney function may lead to kidney disease over time, it is important to confirm the effects of obesity and dietary protein intake on the kidney, especially with the current rise in obese people and the popularity of high protein diets.