Instead of having a set limit for the day (ex. 1600 calories) zig-zaggers will add up all their calories in a week and divide the amount by 7, and the goal is for the average calorie intake to be 1600 (or whatever their personal goal) per day.
This is especially good for people who have natural cycles of very hungry and less hungry days. I was so frustrated trying to get 1600 calories every day. Some days I'd be near my limit before dinner and unable to eat enough to calm my hunger, while the next day I might feel perfectly fine with only 1200 calories under my belt, but I'd feel like I had to force myself to eat another helping in order to get up to 1600.
In the zig-zagging world, it's okay to have a 1200 day, followed by a 2000 day because the average is 1600.
It's not for everyone, since not everyone has cycles between days of being hungry and not so hungry, but it's a way for those who DO cycle to have a plan more custom-fit for their own body.
So come on in, cyclers! I can't wait to see who else joins in



But I've heard other people do seem to get results. And of course, I don't eat the exact same amount every day but it's within a narrow range.