It’s really not experimental though.

Assuming their math and design are good, this is pretty strong, as these things go. But there were a lot of other things that were different between the groups that could reasonably be affecting results.

The article itself is careful to deny drawing any prescriptive conclusions from this research — a tacit acknowledgement that the causal connection isn’t entirely clear.

This is interesting and fairly strong, and potentially important, but definitely needs more work before we start acting on it.

*Quasi-experimental, see my comment below. Excuse the sloppy language, it's a while since I've done one.

It's not as good as an RCT, but lifetime sugar consumption, as the article points out, is not something you can randomise.