How Do We Talk about FAT?

We read:

"Is it OK for doctors and parents to tell children and teens they're fat?

That seems to be at the heart of a debate over whether to replace the fuzzy language favored by the U.S. government with the painful truth - telling kids if they're obese or overweight.

Labeling a child obese might "run the risk of making them angry"."

Source

When I was a kid at school, fat kids got called "fatty" and if you were being derogatory "fatso". They all seemed to survive it pretty well.