The South Beach Diet works by teaching people to substitute bad carbs and fats for good ones. It has three phases. Phase one is the most restrictive and last two weeks. During this phase people eat protein and vegetables and no carbs at all. The protein is lean protein and the vegetables are low-carb vegetables. People eat three normal portion meals and two snacks. The average weight loss during this phase is around eight pounds. Phase two introduces carbs back into the diet. This phase lasts until a person reaches his target weight loss goal and average weight loss per week is one to two pounds. Phase three helps people maintain their target wieght and lasts for life. If the weight starts to increase again, people just go back to phase one.