Not sure but I think it might be cottage cheese thats why you always see it in diet food, on the down side it hardlyy even taste like cheese but thats another story haha.
What Is The Least Fattening Cheese?
According to Celebrities and Cheese the least fattening cheeses are cottage cheese and ricotta, which normally contain around 3% fat. This is in comparison to other cheeses which can contain as much as 50% fat.