I work with dialysis patients. It is a very difficult environment to work in regarding weight. Introducing a concept of Health at Every Size is HARD! (yes, it had to be capitalized)
But today I felt greatly saddened. A patient of mine told me that she had been told, many years ago by a docter, that her kidneys were failing because she'd been fat for so long. I wanted to weep.
Obesity is not a cause of kidney failure. There is a correlation between obesity and Diabetes or Hypertension, the two leading causes of kidney failure, but being fat has never been shown to cause someone's kidneys to stop working.
And this is what a doctor told this patient.
I often go back to my family when I am writing this blog. They are a good example of teh fat peeples. They live in the midwest and are from tall Scandanavian stock (I'm the shortest at 5'6"). My dad's side of the family is all fat. Not just a little fat, either. These are big people. I got this gene.
But here's the thing...there is no history of kidney failure among this family. They have heart disease, sure. There is stroke as they age. And in one part of the family there is a rare bone disease that is unrelated to size. But in general, they tend to die of the things that most people eventually die of and usually pretty late in life (one great-great-aunt lived to 104).
In reality the predisposition for many of these diseases is genetic: diabetes is often seen in families, as is (in my case) hypertension. If this is true of your family, it is important to be screened for this stuff because it can cause kidney failure. But, unless we learn something we haven't yet about the kidney, you won't have a doctor writing obesity as a reason for dialysis any time soon.