Last night I even told my diet group about it.
Now I'm giving you the layman's most simplistic version of it.
The less you eat, the slower your metabolism gets, so the longer you're on a diet, the more slowly the weight goes off, and you have to keep reducing food/calorie intake. Then most people gain the weight back. Recently two friends who have been dieting successfully, that's losing weight, have been told by their doctors that their thyroids aren't working well.
The proponents of the cheating diet say that every week or two you must increase your calorie take with more carbs and fat than usual. Then your thyroid speeds up and you lose more weight.
Today a friend invited me to her place for lunch. She's on a high complex carbohydrate vegetarian diet. Last week, I would have been extremely troubled by her menu. It had more starch than I normally eat in two months. Today I said:
"I'm supposed to cheat to lose weight."
I just hope that I "cheated enough."