I think that simply incorrect, assuming 'studies' != Youtube videos. I know because I've been involved in internet arguments where I've gone looking for studies and found my own argument is incorrect/poorly supported.
To be honest, if you're trying to make my point sound absurd by exaggeration, you've shot way too low. The mainstream nutritional view would be that a Sausage McMuffin every morning on its own isn't going to be a particularly bad thing. You need to be a lot more specific with an overall diet to be a problem. You should have asked something like whether you could find a study about eating nothing but lard is available.
To which my reply would be that the principle of charity would make it clear that in general I meant any semi-realistic nutritional view is available, not that there are studies that prove humans can be healthy on a diet of rocks and asbestos. It really isn't to anyone's advantage if I also have to append to my little post a complete discussion of what is and is not within the boundaries of nutritional theories that have been studied.
I mean... is that... really... what you want...?
I don’t think this is clear to the average person at all.
And that's on harder sciences. In soft sciences (and liberal arts, etc) it's the wild west -- what gets more grants and is more popular at the moment gets priority and is "proved".