https://www.va.gov/OGC/docs/2017/VAOPGCPREC1-2017.pdf
Not sure how helpful this is or if it's already been discuss in regards to the link between weight gain and heart disease/high blood pressure/diabetes.
Obesity doesn't appear to be a disability per say but if using the service connect diagnosis of obesity as a "bridge condition" leading to/contributing to/aggravating other conditions considered disabling then I suppose those conditions would fall into the secondary conditions.
Also, it does appear that hypertension rated at 10% disabiling kinda gives you another 30% under renal dysfunction!
Rating
Renal dysfunction:
Requiring regular dialysis, or precluding more than sedentary activity from one of the following: persistent edema and albuminuria; or, BUN more than 80mg%; or, creatinine more than 8mg%; or, markedly decreased function of kidney or other organ systems, especially cardiovascular
100
Persistent edema and albuminuria with BUN 40 to 80mg%; or, creatinine 4 to 8mg%; or, generalized poor health characterized by lethargy, weakness, anorexia, weight loss, or limitation of exertion
80
Constant albuminuria with some edema; or, definite decrease in kidney function; or, hypertension at least 40 percent disabling under diagnostic code 7101
60
Albumin constant or recurring with hyaline and granular casts or red blood cells; or, transient or slight edema or hypertension at least 10 percent disabling under diagnostic code 7101
30
Albumin and casts with history of acute nephritis; or, hypertension non-compensable under diagnostic code 7101