I keep hearing reference to this but don't know what it is. Thanks

Could it be Dr. Moser's plan of limiting calories to 500 for two days of the week and normal amount of calories the other five days?

Eat what you want five days a week, send your body to starvation mode for two.

Dieters are recommended to consume a ‘normal’ number of calories five days a week and then, for two, non-consecutive days, eat just 25% of their usual calorie total - 500 calories for women and 600 for men.

There are no restrictions on the types of food you can eat and it is suggested that women can expect to lose about a 1lb a week on the diet with men losing about the same if not a little more.