Every time it’s been studied, the best diet for rapid weight loss is generally meat only. This is a diet of only beef, poultry, lamb, pork, veal, fish and shellfish. If you limit yourself to these 7 foods, and you limit yourself to a pound a day, you should be able to lose about 5 pounds a week. Make sure you drink at least a gallon (128 ounces) of non-caloric fluid a day, and you’ll probably need 2 bouillon cubes a day to replenish the salt you are losing. That’s it.