What Is Phase 1 of the Atkins Diet?

Phase 1 of the Atkins diet is also known as the introduction phase and is the most strict phase of the diet. Limiting the total intake of carbohydrates to 20 grams or less per day, Phase 1 of the Atkins diet is the phase that typically results in the greatest amount of weight loss. Dieters are urged to spend no less than two weeks in Phase 1 of the Atkins diet — and longer if possible or if an excessive amount of weight needs to be lost. There are recommended foods that should be eaten during the introductory phase, but there typically are no limits on how much of each food that can be consumed.

The Atkins diet is a low-carbohydrate diet that was invented by Dr. Robert C. Atkins for people who need to lose large amounts of weight. The dieter is allowed to eat nearly all of the meat, fish and poultry that he or she desires, as well as real butter, cream and eggs. Forbidden on the diet are most fruits, vegetables and breads. When beginning Phase 1 of the Atkins diet, the dieter is asked to consume no more than 20 grams of carbohydrates per day. In doing so, the body enters benign dietary ketosis, a condition in which the body begins burning stored body fat.

To verify that the body is in ketosis during Phase 1 of the Atkins diet, the person's urine can be tested using ketone test strips. By placing a test strip into the urine flow, the stick's resulting color can be matched to a chart to verify ketosis. This also can be verified by smelling the breath of a dieter in Phase 1 of the Atkins diet, because the breath is very bad during ketosis. This is caused by the loss of ketones through the lungs.

Other items that should be avoided during the first phase of the diet are alcoholic beverages, caffeine and any food that is made with grains or sugar. Foods that are allowed are cheeses, fats and butter. The restrictions become slightly less restrictive after Phase 1 of the Atkins diet, but the low-carbohydrate focus remains in effect. Water is a recommended beverage, and the dieter is urged to drink at least eight tall glasses of water per day. The dieter also is urged to drink a large glass of water prior to meals and when he or she has a snack craving. The Atkins diet claims that, many times, the body merely needs water when a dieter thinks that he or she is hungry.