No, obviously, I'm rebutting an appeal to authority.

The parent posted a link to a 1,500 word argumentative essay backed up with inline references to 19 peer reviewed journal papers and included the words "check it out here and make up your own minds". Instead of making any comment on the content of said essay, you merely compared credentials of the speakers.

Which poster seems more guilty of a fallacious argument?

Did you actually read the linked articles and the referenced links? They don't say what the AA claims they say. He makes scientific statements that can generally be inferred from the cited sources, but which the sources don't actually prove.

It would be like some guy saying that physical money is bad and referring you to a CBO publication about hyperinflationary currencies.

I read both links but only 4 abstracts of the referenced articles (which on their face seemed legit but I did not have access to the full articles. His analysis of the last 37 years of American diets seemed accurate based on http://www.ers.usda.gov/Data/FoodConsumption/ compared to what Dr. Lustig cites for 6 years for children.)

If you disagree with one of his conclusions, please post your thoughts - but be specific. I'm open minded... if "He makes scientific statements that can generally be inferred from the cited sources, but which the sources don't actually prove"...I'm happy to agree with you but that seems like that would be simple to show but you don't link to anything or provide any arguments or even a sentence or two to back it up.(?)

I don't have a horse in this race, but I'm not going to discount someone just because they aren't a professor at UC-SF.

The problem with this comment is that it assumes I have a horse in this race too. I think maybe you'd have been better off posting a comment on the root of the thread rather than attaching it to mine.

This right here is one of the more annoying message board tics.

I'm pretty sure that's not what people mean when they talk about appeal to authority. An actual appeal to authority is fine. A fallacious appeal to authority is one where the 'authority' in question has little or questionable authority in the area being discussed.

Here is a possibly legitimate appeal to authority, although you could refute it on its own grounds :-) http://en.m.wikipedia.org/wiki/Argument_from_authority

An actual appeal to authority isn't "fine", it's saying

"Accept my logic as correct because I namedrop a well regarded name as a supporter". But since well regarded people can be wrong this is no sort of proof at all.

I think you need to read the Wikipedia entry on Argument from Authority.