In the first two weeks of the Atkins diet, a person is allowed to have 20 grams of carbs a day. After two weeks, the amount can be increased by 5 grams, according to About.com.
The Atkins diet is based on the idea that limiting carbohydrate intake encourages the body to burn fat as fuel. About.com states that this process, known as ketosis, affects insulin production and limits an individual's craving for the types of carbs that promote weight gain. The long-term aim outlined by About.com is to keep carbohydrate intake below 40 grams a day and to remove refined carbs, such as white bread, from the diet completely.