>For two weeks. Which is effectively nothing when you are talking about long-term issues like nutrition, health, weight, etc.

Yes, for two weeks, that's what the author is talking about. You are talking about something different. Can you point to the part of the article where this person recommends eating 500 calories of potatoes, as you say, "long-term"?

I find it hilarious that some innocuous article like this appears and people want long-term, double blind studies or it's trash. Meanwhile, any time air quality articles come up, half the same audience claims they can detect 100ppm changes in room CO2, it makes them sick, etc etc.