The promise of evidence based medicine has only been partly delivered. The profit motive has biased research and stopped the release of research that's doesn't favour existing business investments.
The Women's Health Initiative is an excellent example of a study with a very clear result, that was burred because it didn't align with expert opinion at the time.
For at least 50 years the best advice on how to lose weight has been deigned "by the experts". Even when the solution is free and widely available (but not profitable).
This is worksheet seven of eleven. Collect the set.