I don't know how it works for others, but it worked for me. Over the past several years, I've lost close to 200 lbs (340/145), but I'm a post-menopausal, hypothyroid woman who had to severely restrict calories in order to lose.
Once a week, I ate freely--still primal, but much higher calorie than usual. I don't know whether it helped, but it didn't hurt, and I didn't experience any stalls at all while doing this. I never did this more frequently than once a week, and sometimes it was once every two weeks.