It went from morbidly obese to morbidly obese.  Nothing real accomplished. In all likelihood it lost weight due to pissing out glucose from uncontrolled diabetes.  When your blood sugar gets high enough you begin spilling sugar in your urine.  At only 1.6lbs per month of weight loss, that's only a 188kcal a day deficit.  Entirely reasonable for unexpected weight loss due to glycosuria.