The overall rule for 5:2 is the same as with everything else. Consume fewer calories than you burn. The 5:2 for some just make it all more accomplishable.
If you simply count calories, then you can always eat anything you like. You just have to fit it into your food diary.
Doing the 5:2 can make the "feast" days more enjoyable - but be careful. It's NOT a free-for-all, and if you have a problem with overeating to begin with, then it can easily get you in trouble.
If you can control it, then it's a great tool.
"Losing weight is never about eating as little as possible"
"Eating enough, moving more, not eating stupid s**t = losing weight."
"Do. Or do not. There is no trying."
- Master Yoda.
I started my weight loss journey on October 4th, 2010 - and this is what I have accomplished so far: