I totally get what you’re saying.
If I don’t exercise, my waistline expands and my weight goes down.
If I stop eating because my pants don’t fit any more, I have to start exercising daily, otherwise my body consumes the muscle instead of the fat, and my waistline stays the same even though my weight goes down even more.
Back when I was in my mid-30s I was fighting or practicing three to five times a week, was just under 6’2" tall, had a 34" waistline and weighed 220 lbs.
According to the chart, I was obese - but at the time, people claimed my facial features were so lean as to be “skeletal” (totally not kidding, it was a running joke for decades).
I have no idea if this is a quirk of my own physiognomy or something totally commonplace. Or if it’s related to my diet - I don’t like sweets and I’ve always eaten mostly meat and raw vegetables.
But the idea that you accurately gauge how fat a person is by their height, weight and age is pretty loopy. You’d be better off just looking at silhouettes, and even that would only give a coarse scale.
