I have the original Mayo Clinic diet from the 80's the one that used to photocopied and passed round offices. It's as follows
Breakfast - the same every day, 1 or 2 eggs, half a grapefruit and black coffee
Monday
Lunch - all the fruit you can eat
Dinner - 2 eggs, green salad and one piece of dry toast
Tuesday
Lunch - chicken and tomatoes
Dinner - Steak, tomatoes, green salad and olives
Wednesday
Lunch - eggs, tomatoes and coffee
Dinner - 2 lamb chops, celery, cucumber, tomatoes
Thursday
Lunch same as Monday
Dinner - 2 eggs, cottage cheese, cabbage and a piece of dry toast
Friday
Lunch - Eggs, spinach and coffee
Dinner - White fish, mixed green salad, 1 piece of dry toast
Saturday
Lunch - 2 eggs spinach and coffee
Dinner - steak, celery, tomatoes, and cucumber
Sunday
Lunch - same as Monday
Dinner - chicken, tomatoes, cooked cabbage, grapefruit and coffee
No alcohol allowed, and nothing to be cooked in fat - it's not bad for you at all, if a bit tedious, and is excellent for shifting the flab for a holiday or special occasion