The Challenges of Observational Trials

I feel like observational trials fail us continuously. And then randomized controlled trials are just difficult to do, unlikely to really lead us in clear ways. If we don't have data, then it just opens this space for a lot of completely wacky recommendations which are based on theories. I'm kind of left here with what I think is common sense, right? You're avoiding high-process food, you're eating a lot of good normal, natural stuff,. But I don't know, am I any better than anybody else by recommending that diet?