From The New York Times: PHYS ED: How Exercise Changes Fat and Muscle Cells Several striking new studies provide some clarity by showing that exercise seems able to drastically alter how genes operate, perhaps altering the risk for problems like obesity and diabetes. http://nyti.ms/18QHe5l Here is another link to the same article. http://well.blogs.nytimes.com/2013/07/31/how-exercise-changes-fat-and-muscle-cells/?_r=0