I think the very word 'fact' is open to question. Many 'facts' over the decades have been shown to be misguided opinion.
It's obviously best to stick to proven science if one can, but nowadays researchers seem to contradict themselves daily, and one is left wondering what is true.
This is especially the case with what constitutes unhealthy food.

Regarding personalities and the character of various politicians, I think one's instinctive feelings can be a good guide.
I have never met Trump, but just looking at his facial expressions and body language, let's just say I wouldn't buy a used car off that chap!