No, but what's good for the gander is usually good for the goose (I know its a rephrasing of the original). That's how we get effective medicine and built model

No, but what's good for the gander is usually good for the goose (I know its a rephrasing of the original). That's how we get effective medicine and built models of understanding. While individual factors are prevalent, they usually don't cause as much deviation from the overarching model. For example, higher intake in fruits and vegetables is a practical step, easily understood, and well studied to help reduce meat related illnesses like heart disease and CVD. While the mechanisms aren't well understood, that doesn't preclude the data.