It's funny because one of the studies that reflected an 800 calorie diet (They were trying to see the effects of a starvation diet on the human body), had to stop prematurely. The reason? The human subjects became severely sick and their weight loss was too rapid. An 800 calorie diet, 3 meals a day, would mean 267 calories per meal. A simple Wendy's cheese burger has 950 calories minimum, with fried and drink, you're looking at 1850 calories for ONE MEAL.