This article, basically a puff piece for how great and safe GBS is and how its a diabetes cure, references a small study which showed fat diabetics who have GBS lose less weight on average than those fat people who do not-have diabetes that is.
I learned that losing 40% of "excess weight", not weight at surgery as I thought, is considered a success for the procedure. Of 310 patients studied, 92% who weren't diabetic achieved that figure, and 79% of those who had diabetes.
No one is sure why. The speculation from Dr. Guilherme Campos, head surgeon at the bariatric facility concerned noted though the procedure is the same, surgeons use internal the persons anatomical markers as to how to shape the reduced stomach.
I wasn't sure why that was relevant unless those tended to vary according to having on not having type two diabetes. Ditto the flexibility of the stomach, with regards to its capacity to recover its previous size. That sometimes is total or as near as before, meaning between 5% -15% of GBS patient lose no or little weight.
A more pertinent possibility was mentioned- medication taken to combat the condition. Which tends to preserve weight due to actions to regulate, lower blood sugar. I'm not sure how that's related to what happens when that energy when is driven to exit the blood.
It's a salient connection, lowering of blood sugar with weight preservation/ gain, which points to weight's defensive possibilities. That would be a connection to uncover properly.
I note Campos himself defines diabetes as "a consequence of being overweight." If that was the case, all fat people would have it and no slim people. Clearly there's the usual question of direction of cause plus the influence of innate susceptibility.
As I mentioned, its just as easy to explain the other way around. Fatness is a defence, self management, or a side effect of the development of diabetes.
The argument against that is lifestyle change staves off the onset of diabetes, even reverses it, which would again be to do with the alteration in the body's use of energy. What would be intriguing is to find out exactly what is going there.
It's been noted that the so called curative affects of GBS kick in before any real weight loss can occur, which is to do with the re-routing i.e. bypassing of part of the small intestine. Another example of a change in the processing of energy.