[lolinder]

Isn't a simple possible explanation that people who are at high risk of (or already diagnosed with) these diseases make up a disproportionate chunk of the lowest sweets consumption bracket, simply because they're the ones who are actively restricting intake on advice from doctors?

I'd naively expect most healthy people to fall in the second-to-lowest bracket—they're not actively restricting, but they don't have the pervasive bad habits of the highest consumers.

[kristjansson]

This is exactly what happened with the “red wine is good for you” claim

[ricardobeat]

That was my first thought as well, but the paper says that after excluding all people with a previous condition, that association remains unchanged. There might be something else, like particular diets, at play.

[lolinder]

That would rule out pre-existing conditions but not rule out people who already knew they were high risk for reasons other than a previous diagnosis (such as blood work, family history, etc.).