Like any area, the ethics boards hold experiments to much higher standards than things like surveys; I don't think it's exceptional in this regard except to the extent that the area has irresponsibly taken its dubious results as gospel and tried to remake society. (I criticize a lot of psychology for bad research practices, but at least with most of it, people don't try to reorganize their lives and diets based on the latest survey.)

On top of that, diet research focuses heavily on junk correlations because it's unusually hard to run RCTs on diet. Unfortunately, they ignore that correlations are far less informative compared to causations than correlation research is easy to run compared to RCTs. We'd be better off if most diet research had never been done, ethics ignored, and the funding used for a few large RCTs instead. That'd've avoided the farcical history of diet advice like salt, fat, etc.