The South Beach diet has three phases. During the first of the South Beach diet phases, no carbohydrates, fruit or sugar can be eaten.

After 14 days, the diet enters the second of the three South Beach phases, during which some carbohydrates, such as whole grains, are gradually reintroduced. Phase two continues until you have achieved your target weight.

The third phase is carried on indefinitely, and involves turning healthy eating into part of your daily lifestyle.

This three-phase plan was devised by cardiologist Dr Arthur Agatston primarily to enable his heart patients to lose weight healthily, and keep the weight off long-term. Although the first phase of the diet does cut out carbohydrates completely, this is not a carbohydrate free plan. Cutting out all carbohydrates is primarily used as a short term measure to kick-start the process of weight loss.

But the diet's creator believes that some carbohydrates are necessary for nutrition in the longer term. Instead of cutting out all carbohydrates in the diet's second and third section, it distinguishes between 'good' and 'bad' carbohydrates. This is based on the 'glycaemic index', in which foods with a low glycaemic index take longer for the body to turn into sugar, thus avoiding a 'sugar rush', which can leave you feeling hungry again very quickly. In the second section of the programme, you can eat normal sized portions of food, and also eat two snacks a day in addition to your three main meals, as long as you eat only low 'GI' foods.

The third section of the programme allows slightly more leeway, but still focuses on a low 'GI' diet, and is intended to become a permanent healthy eating plan.