I figured the same thing--I definitely didn't feel like I was cutting calories in any way. I took up drinking lots of whole milk, eating bacon, and at my desk I'd eat a whole 12-ounce coffee cup full of mixed nuts (still do, in fact) each day at work. I didn't even cut carbs, I ate pizza and pasta pretty regularly. The only thing I did was aggressively eliminate refined sugars and beer from my diet.
I'm curious if gut fauna could be a factor.