It appears as if the classic grapefruit diet is the same sort of low/no carb fare that would be popularized decades later by the Atkins and South Beach diets!
I don't know if fried meat should be given quite the pass suggested here. But the basic contours of the diet: protein with every meal, carbs mostly from vegetables, caffeine from the coffee or tea ... are all pretty sound. And I've read that grapefruit does have some excellent fat-fighting characteristics.
I also just prefer to eat less frequently. I understand the idea of eating a lot of small meals throughout the day. But I'd rather have as little food in me as is necessary. I think one of the things about jiu jitsu compared to other sports or even other grappling sports is that it really helps to maximize your body's ability to move and bend. There are three main ways to do this: get leaner, get more flexible and avoid encumberances (such as a belly full of food). I'm looking to accomplish all three.
The Original Grapefruit Diet
BREAKFAST
1/2 grapefruit or 8oz pure grapefruit juice
2-3 Eggs any style
2-4 Slices of bacon
Black coffee or tea
LUNCH
1/2 grapefruit or 8oz pure grapefruit juice
Any Meat cooked in any style including fried
Salad using any red and green vegetables with lots of dressing
Black coffee or tea
DINNER
1/2 grapefruit or 8oz pure grapefruit juice
Any Meat or Fish cooked in any style including fried
Green or red vegetables with lots of butter
Black coffee or tea
BEDTIME
8oz Tomato or Vegetable juice
NOTE
Take a multivitamin daily
Do not eat between meals
Eat till you are full at meals, double helpings if needed.
Drink six to eight glasses of water a day
FORBIDDEN VEGETABLES: Potatoes, peas, carrots, corn
RED AND GREEN VEGETABLES: Celery, red onions, peppers, radishes, broccoli, cucumbers, green onions, spinach, cabbage, tomatoes, green beans, lettuce, pickles.