South Beach diet

The South Beach diet is a three-phase, carbohydrate-restrictive diet. It emphasizes foods that are low on the glycemic index (GI) and low in saturated fat, such as lean meats, vegetables, cheeses, nuts, and eggs.

Unlike other carbohydrate-restrictive diets, such as the Atkins and Zone diets, the South Beach diet promotes “good” carbohydrates, such as whole grains and fruit.

The creator of the South Beach diet, Dr. Arthur Agatston, is considered a leading cardiologist and is the director of the Mount Sinai Cardiac Prevention Center in Miami Beach. Originally, he had intended to design an eating plan to improve the cholesterol and insulin levels of his patients.

However, Dr. Agatston soon discovered that his patients also lost weight on his plan. After further research, he approached Marie Almon, R.D., chief clinical dietician at the hospital, to help develop the eating plan into an effective diet.

The results became the South Beach diet. Having sold more than a million copies since its publication in April 2003, The South Beach Diet book has remained on the New York Times bestseller list for over a year.


The primary benefit of the South Beach diet is considered by many to be its initial rapid and significant weight loss—8–13 lb(4–6 kg) in the first two weeks. After the first two weeks, weight loss continues at a slower rate, averaging 1–2 lb (0.4–1 kg) weekly.

In addition to weight loss, the diet reduces cholesterol and insulin levels, thus reducing the risks of diabetes and heart disease. It is claimed that the diet is easy to follow because it is designed to eliminate cravings and has more flexible food options after the first two weeks.


In his book, The South Beach Diet, Dr. Agatston states that “this diet is not low-carb. Nor is it low-fat.” Instead, the diet focuses on eating the “good” carbohydrates (fruits, vegetables, and whole grains) and “good” fats (olive oil and nuts) rather than eliminating them from the diet entirely.

Dr. Agatston based the core of his dietary plan around the glycemic index –the increase in blood sugar levels by foods containing carbohydrates during a set amount of time.

After consumption, food is metabolized into sugars and promotes the release of the hormone insulin. When the blood contains excess sugar, insulin removes it from the blood stream by storing it in cells, including fat cells.

High-glycemic carbohydrates (greater than 70 GI) are metabolized rapidly, which causes elevated insulin production. High levels of insulin result in more blood sugar being stored as fat, thus causing weight gain.

This pattern induces craving for more carbohydrates, thus leading to the consumption of more high-GI foods. Low to moderate-GI foods, however, raise insulin levels more slowly and sugars are metabolized more effectively, thus reducing the amount of blood sugar stored as fat.

Cravings for more food is reduced. In addition, by eating these low-GI foods, the risk of insulin resistance that can lead to atherosclerosis and diabetes is reduced. As such, Dr. Agatston designed the South Beach diet to promote foods low on the GI and eliminate the body’s craving for high-GI foods.

The South Beach diet consists of three phases. Phase one is the strictest part of the diet and lasts for two weeks. The purpose of Phase one is to banish the dieter’s cravings for high-GI foods such as bread, rice, potatoes, pasta, and sugar. Alcohol, fruits, cereal, and such vegetables as carrots and corn are also restricted during Phase one.

Instead, protein-rich foods are emphasized, such as lean meat, fish, eggs, cheese, nuts, and vegetables. Coffee and tea are also allowed. Three regular-sized meals are eaten each day, supplemented by mid-morning and mid-afternoon snacks as well as dessert.

During this period, the body chemistry will change dramatically until cravings for high-GI foods are eliminated and insulin resistance is improved/lowered. In addition, rapid weight loss is typically experienced.

Phase two reintroduces several of the restricted foods and encourages eating from all the dietary food groups, the expected result being that the body will neither crave high-GI foods nor store food as excess fat to the same degree. Such high-fiber carbohydrates as whole-wheat pasta and bread and most fruits are now permitted.

Moderation remains the key to success for this phase and low-GI foods are strongly encouraged. Phase two continues until the dieter reaches his or her ideal weight, ideally averaging a loss of one to two pounds per week.

Phase three, the ultimate goal, focuses solely on weight maintenance. Having reached the ideal weight, the dieter now makes the changed eating habits a lifestyle from this point forward. Basic dietary techniques are still maintained.

Only the high-GI foods and “bad” fats from the previous two phases continue to be restricted. Altered body chemistry will promote long-term cardiovascular health and reduce the risk of diabetes. Should weight gain occur, Phase one of South Beach diet is reintroduced until the weight goal is achieved.


There are no initial preparations required for the South Beach diet. However, as with most diets, it is wise to consult with a physician beforehand. Blood testing for insulin, glucose, and cholesterol levels is suggested. It is strongly recommended that dieters taking medications for medical conditions such as heart disease consult a physician before going on the South Beach diet.

Similarly, diabetics on insulin or other medications are advised to have a doctor monitor their blood sugar regularly and determine if they are at risk of kidney impairment while on the diet. It is also recommended that a registered dietitian be consulted to determine the dietary needs of certain medical conditions, such as pregnancy.


The South Beach diet is not recommended for people suffering from or at risk of kidney problems. The diet’s high protein content can place increased strain on the kidneys, possibly causing long-term damage as well as kidney stones and bone loss. Additionally, the possibility of ketosis-induced dehydration during Phase one can increase the risk of further kidney impairment.

Dehydration occurs when the body experiences water loss with accompanying loss of important blood salts like potassium and sodium. Ketosis occurs when carbohydrates are not available and the body burns an excessive amount of fat, during which some ketones, or fat fragments, are excreted.

The restrictive nature of Phase one may also induce mineral and vitamin deficiencies. Remaining in Phase one of the diet for longer than two weeks greatly increases the risk of losing bone and muscle mass. Dieters should remain in Phase one for no longer than three or four weeks.

Some nutrition professionals contend that the South Beach diet menus provided in the book lack important nutritional information and detailed portion sizes as well as specific substitutes for foods the dieter cannot or will not eat.

They claim that these aspects, combined with the restrictive nature of the diet, can make sticking with the South Beach diet on a long-term basis difficult for some people. Also, they assert that the diet does not emphasize an exercise regimen and that exercise is vitally important to avoid the loss of muscle and bone mass, especially during Phase one of the diet.

Side effects

Despite Dr. Agatston’s claims to the contrary, the South Beach diet is both a low carbohydrate and a low fat diet. For this reason, one main concern regarding the diet is the risk of ketosis, especially during Phase one.

Ketosis can cause such symptoms as dehydration, dizziness, heart palpitations, fatigue, lightheadedness, and irritability. Hypoglycemia, low blood sugar, headaches, and excessive fluid loss are also commonly associated with this diet. Cramping and tired muscles can be incited by salt depletion.

Kidney functions can be impaired, possibly leading to serious health issues. Kidney function can be further impaired by the diet’s high protein requirements. These side effects typically lessen or fade at the beginning of Phase two, when a more balanced diet is undertaken.

Research and general acceptance

Unlike the majority of low-carbohydrate diets, the medical community generally accepts the South Beach diet. The South Beach diet contains all the major food groups, promotes ingestion of “good” fats for maintaining heart health, and is flexible enough to accommodate most dietary needs.

However, many clinicians and dietitians agree that the rapid initial weight loss results mostly from water loss. Much of this weight can return once the dieter rehydrates.

Another important criticism by medical and nutritional professionals is the lack of evidence to support Dr. Agatston’s claims connecting the consumption of low-GI foods and weight loss.

They assert that as of the early 2000s, there is no scientific proof that eating low-GI foods will have any more weight loss effect than eating a normal, calorie-reduced diet that includes carbohydrates; that Dr. Agatston also fails to take into account the interaction of different foods when eaten together, which can dramatically alter glucose metabolism; and that this failure means that utilizing the Glycemic Index as a gauge for what foods to eat is not only confusing but also slightly misleading.