There's a lot of other stuff going on inside your body
Obviously, weight plays a role in a person's health, but it's not exactly a black-and-white issue. Some people can be 50lbs overweight and still run a marathon, while others at a perfectly normal weight get winded walking up a flight of stairs. It’s best to leave an official assessment up to doctors, who can perform a series of tests to more directly gauge overall health.
“Tests that are very useful to convey [health] risks [include] blood sugar, HDL levels, and elevated triglycerides or LDL (bad cholesterol),” says Dr. Caroline Cederquist, founder of the diet delivery program BistroMD. Performing a hemoglobin A1C test is a good indicator of of how your body is using glucose, she adds, as is a fasting insulin test, both of which can show indications of pre-diabetes. Although these complications are commonly associated with lifestyle, some people are more genetically predisposed to high blood sugar or bad cholesterol, despite being a normal weight.
Examining overweight patients also involves looking at two factors besides weight: one is metabolic risk, which refers to illnesses like type 2 diabetes, high blood pressure, and high cholesterol. The other is fat mass consequences, which are basically all the mechanical realities that come with gaining a bunch of weight (joint pain, sleep apnea, acid reflux, etc.). Basically, is a person so fat that it hurts their knees to walk, or prevents them from falling asleep? If neither of those issues is present, it’s safe to assume a patient is relatively healthy, despite his or her weight.