Lipedema has no known cause. It is fat which is stored but cannot be used because the lymph/drainage/transport pathways in the area of the body affected don't work well enough to transport fat out of that area of the body (could also be because of soft tissue surrounding the fat cells in these areas, not too sure on that one though). Scientists also believe there is a strong hormonal component to this disease. It results in tenderness in the affected area, swelling that can be partially alleviated by elevating the legs, and fat from that area being unable to be transported from that area of the body. So, exercise and healthy eating can make small changes to the area affected (muscle "tightening things up", what little fat that can get out gets used, etc.), but overall fluid and fat retention will make that part of the body disproportionately large compared to other areas of the body. That being said, in my personal opinion, lipedema is like other inflammatory or hormonal diseases: definitely exacerbated by obesity and in some cases aren't even an issue until a person becomes overweight enough to strain their lymph or hormonal systems.