They're in the top 10 for the lowest obesity rate worldwide. An overweight person isn't someone with a problem there, it's just someone who knows their food.

Yeah, I was surprised by this too. The character almost always has a box of fries in her hand in the manga, so it makes sense that she is associated with fries. However, like you said, if this is a trade association meant to promote fries, then it is questionable whether this is actually helping.

It's a little funny, but I don't see it as a misstep. It's probably just a popular (I assume) character who's associated with fries, and them being realistic in assuming that it's common knowledge that over-indulging in fast food causes weight gain.

The story is kind of a reverse isekai, where a bunch of fantasy characters end up in the real world and have trouble with modern fast-food.

So yeah.

Now I can't unsee Zelda in this character design...

I tried to look them up and didn't find much, but I did find this:

The Seven Principles of the Japan French Fries Association:

1. Love French fries and eat them at least once a week.

2. Eat all the French fries you are served.

3. Do not pressure others to like French fries as you do.

4. Do not persecute those who dislike French fries.

5. Do not blame French fries for making you fat.

6. Do not use French fries to commit a crime.

7. Honor and respect those who grow potatoes.

Like France?