I'm something of a nutritionist myself (I'm not, but I did lose 240lbs in the span of 1.5 years).
I'm not saying that makes me credible, especially because I'm "hiding" behind the crux of ai generated content. But, I do my research and prove whatever is in the videos by referring to journal articles in the description of each video. You do have to read them to find out that I'm telling the truth, but the information is all there.
Ultimately, YOU as the viewer should always be doing your research regardless. Don't take the words of anyone at face value. Verify facts with your own two eyes and disregard them otherwise. I know I would if I were you.