Hi Libby,
As Barb said, if you always consume the same number of calories, your body adapts to that amount. Especially if your calories are lower than what is required to maintain your weight, the body goes into "starvation" mode and slows your metabolism to cling to every pound. The theory of the "zig-zag" diet or "calorie shifting" is that by varying the calories you take in on a daily basis, you can "trick" your body/metabolism & help avoid this slow down. Eating smaller, more frequent meals also helps to do this.
I've never tried the official "Zig-zag" diet which I've read demands very strict adherence to certain menus/foods & times of eating. I do, however, vary my daily calorie totals between 1200-1600 or so and I find that doing this helps me lose weight faster than eating the same number of calories every day.
This is a site where you can plug in your height/weight/activity level and have your daily caloric needs calculated to maintain & to lose weight. Also, about 1/2 to 2/3 of the way down the page is a "7 day calorie shifting" link that will calculate how many calories to eat each day to vary the daily totals but still add up to the same amount for the week. It doesn't give you specific menus/food recommendations; most of the sites that do this charge a fee. The site to calculate your daily caloric needs (and a variable day/consistent week total) is: http://www.freedieting.com/tools/calorie_calculator.htm
While most people report a large & quick weight loss initially on the zig-zag, there is disagreement as to whether it is a lasting weight loss. Some reviewers also report that the menus provided by most of the "pay for info" sites are deficient in veggies and thus in vitamins; some reviewers also report deficiency in other nutrients, including calcium.
You can find info by gooling "zig zag diet" and/or "calorie shifting". Here are just a couple of sites:
http://diet.lovetoknow.com/wiki/Calorie_Shifting
http://eatknowhow.com/2008/03/17/calorie-shifting-fad-and-facts/
http://healthylossdiet.blogspot.com/
Well it's not exactly a official diet but I'll try it. :) i want to look nice for my first highschool dance
I'm not familiar with anything called the "Zig Zag" diet; however, it's always a good idea to vary your calorie intake on a regular basis in order to keep your body from becoming used to the same amount of food every day.
I'm not aware of anyone on this forum currently on this specific diet.