CAR, sorry to hear about your sister. Just remember, no one here is saying there’s no metabolic differences. And it is true, if someone is genetically overweight, they will be healthier staying overweight. What I have seen however is because of the changes we have induced for ourselves over the last 50 years, a lot of the genetically overweight are now obese, and this is quite concerning.
The same can be said for a lot of Filipinos I know. They are meant to be skinny people, and what is happening is a lot of them are overweight, and their bodies can’t handle it. They develop diabetes, hypertension, cholesterol problem, and gout just by being overweight.
Lastly, you are right about people that over do the exercise. There is evidence that extreme exercise leads to cardiac scarring.
The Buddha was very wise in his advocation of the middle path. Most things in life are truly better in moderation.