[pessimizer]

> Doesn't the risk of being overweight completely overwhelm the risk of a not-yet-understood gut flora change?

It's possible that becoming overweight could cause a gut flora change, or a gut flora change could make you likely to become overweight.

There's no benefit to ending research into diabetes after you find an association between overweight and diabetes, or in making an assumption that the condition of one's gut flora and being overweight are independent.