Food Choices Study

I came across this article on the internet, and it was both interesting and frustrating.

Potatoes bad, nuts good for staying slim, Harvard study finds

Some of the analysis is interesting, and probably all of it is worth further study, but I worry about the tangible usefulness of it. I'd like to know what sort of attempts they made to eliminate other variables, though, specifically calorie intake. Like this analysis:

"Potatoes fared particularly poorly, possibly because starch, like refined grains and sugar, is less satisfying, so people eat more."

The "eat more" comment makes me think that they didn't try to isolate food choices from calorie intake when determining the effect of food choices. Like, potatoes leave you hungry, so you eat more calories if you eat potatoes. Well, shit, if you eat 9,000 calories of bananas every day, you're gonna get fat. It's 9,000 goddamn calories.

If they didn't try to account for differences in calorie intake, I'm not surprised that yogurt came out as a good food. Nobody who's not on a diet eats yogurt. Nobody.