The South Beach diet is a commercial weight-loss plan created by Miami cardiologist Arthur Agatston. It consists of three phases: phase 1, a two-week low-carbohydrate phase during which dieters eliminate all fruits and starches like bread and pasta; phase 2, the long-term portion of the diet that dieters follow until reaching their goal weight; and phase 3, the maintenance segment of the diet, which is followed for life.
The South Beach diet started as a weight-loss plan that cardiologist Arthur Agatston developed for his overweight patients who had trouble staying on the standard low-fat, high-carbohydrate diet recommended by the American Heart Association. The Miami doctor questioned the concept that there could be too many fats or carbohydrates in a diet, wondering instead if people consumed the wrong types of fats and carbohydrates. Agatston first tested the theory of “good” and “bad” carbohydrates on himself, giving up his late-afternoon snack of a low-fat, sugary muffin. After two weeks, he had less belly fat and more energy, according to Agatston's 2008 book, The South Beach Diet Supercharged: Faster Weight Loss and Better Health for Life.
South Beach Diet products
Calories per serving
360 or less
Wrap sandwich kits
250 or less
Frozen breakfast wraps
200 or less
Meal replacement bars
Cookies and crackers
100 or less
Agatston gave his patients copies of lists of foods to enjoy and foods to avoid. Patients who followed the diet lost belly fat and lowered their cholesterol levels. As they saw results, patients gave copies of the diet to their friends. People began calling the Florida doctor's weight-loss plan the “South Beach” diet, a reference to the trendy Miami neighborhood of South Beach.
Agatston and his colleagues described the success of the diet at medical conferences, including the 1999 national meeting of the American College of Cardiology. In 2003, Agatston published the book The South Beach Diet: The Delicious, Doctor-Designed, Foolproof Plan for Fast and Healthy Weight Loss. Television coverage boosted the popularity of the South Beach diet, and in 2004, Kraft Foods entered into an agreement that allowed it to use the South Beach diet name on a line of foods that were nutritionally compatible with the diet. (The arrangement with Kraft Foods was no longer in effect as of July 2012.)
Agatston wrote additional South Beach Diet–related books and cookbooks. In 2008, he updated his diet with the changes described in the book The South Beach Diet Supercharged: Faster Weight Loss and Better Health for Life. The changes included the addition of 100 foods to the first two phases of the diet and an expanded plan for physical activity, The South Beach Supercharged Fitness Program.
As of January 2018, Agatston maintained a Florida cardiology practice that emphasized disease prevention. He served as medical director of Wellness and Prevention at Baptist Health South Florida. The South Beach Diet website offered recipes, a weight tracker, and other tools to paying diet-plan members. In addition, South Beach food products like Protein Fit cereal bars were sold in chain grocery and drug stores.
The South Beach diet starts with a very restrictive first phase, followed by a longer phase that offers more food choices and a third phase focused on weight maintenance. Phase 1 is a basic low-carb, high-fat diet that forbids all sugars and starchy foods such as bread, pasta, and potatoes. Phase 1 is designed for people who need to lose more than 10 pounds (4.54 kg). People could lose 10–13 pounds (4.54–5.90 kg) during this phase, according to Agatston.
After two weeks on phase 1, dieters switch to the phase 2 plan. This segment of the plan is also the start of the diet for those who need to lose 10 pounds (4.54 kg) or less. People should lose 1–2 pounds (0.45–0.91 kg) per week, and will remain in this phase until reaching their weight-loss goal. Phase 3 consists of lifetime maintenance. Agatston maintains that dieters do not feel hungry because the plan features three meals, at least two snacks, and an occasional dessert.
The South Beach diet is based on the idea that to lose weight and to obtain health benefits, the dieter must replace bad carbohydrates with good carbohydrates and bad fats with good fats. “Good” carbohydrates are found in vegetables, fruits, legumes, and whole grains, which are rich in nutrients and dietary fiber. Carbohydrates include sugars, starches, and fibers. Processed grains, like those in white bread, contain carbohydrates without the health benefits of fiber and some vitamins and minerals. The good fats on the South Beach diets refer to monounsaturated or polyunsaturated fatty acids. Unsaturated fats help to reduce blood cholesterol levels, whereas saturated and trans fats (“bad” fats) may contribute to high cholesterol and heart disease.
When people eat foods that contain carbohydrates, digestible carbohydrates are broken down into glucose (sugar) that enters the bloodstream. The blood sugar level rises, and cells in the pancreas produce the hormone insulin. The insulin signals cells in the body to convert some of the glucose not used immediately for energy production into a compound called glycogen that is stored in the liver and muscles. Some glucose is converted into fat and stored in fat cells. When blood glucose levels go down, other cells in the pancreas release the hormone glucagon. Glucagon signals cells in the liver and muscle to release glycogen, which is converted back into glucose and is burned by the body. If glucose levels remain low, fat is also burned for energy.
The intake of foods containing a large amount of sugar or simple carbohydrates that break down rapidly causes insulin level spikes. When people eat carbohydrates that break down more gradually, their insulin level rises more slowly and does not reach as high a level. Eating too many sugary foods too often releases a great deal of insulin. If the sugar in the blood is not used to provide energy for the body's use and if the glycogen storage is maximized out, the extra sugar will be converted to fat to be stored in fat cells. Eventually, cells in the body may become insulin resistant, which can result in type 2 diabetes. The South Beach diet claims to eliminate insulin resistance by removing all fruits and starches from the diet for two weeks. Good carbohydrates also contribute to a sense of feeling full for a longer time than the bad carbohydrates.
In the South Beach diet, good carbohydrates are defined as those with a low glycemic index (GI), while bad carbohydrates have a high GI. The index compares foods on a scale of 1–100 based on how much they increase the level of glucose in the blood. Foods with a low GI raise blood sugar less than those with a high GI. Depending on which authority is consulted, a low index is considered 50–55 or lower. Some authorities define above 51 as the start of the high GI rating; others rate it as 65 or higher, with a medium index ranging from 56 to 69.
Some permitted foods in phase 1 include:
Phase 1 foods to avoid include:
After two weeks on phase 1, the dieter gradually reintroduces foods into the diet that were prohibited during the earlier phase. Weight loss in this phase is expected to be 1–2 pounds (0.6–1 kg) per week, and the person remains on Phase 2 until reaching his or her weight-loss goal. Permitted foods include phase 1 foods and:
Foods to avoid include white potatoes, white-flour products such as pasta and rolls, canned fruit, watermelon, raisins, beets, corn, and ice cream.
Once a person reaches his or her weight goal, no foods are prohibited. However, foods should remain portion controlled, and any treats should be eaten in moderation.
The restricted diet during phase 1 of the South Beach diet is designed to produce rapid weight loss. During that time, dieters lose belly fat and gain awareness about their dietary choices. Once their weight-loss goal is achieved, dieters have the ability to make wise food choices while occasionally enjoying less healthy selections.
According to Agatston, benefits of the South Beach diet include:
The South Beach diet ranked as the 22nd best diet overall in the U.S. News & World Report's 2017 evaluation and ranking of the 25 best diets. The requirements for placement in the top 25 were that the diet was relatively easy to follow, nutritious, safe, effective for weight loss, and effective against diabetes and heart disease. The diet also ranked high for short-term weight loss, but reviewers disliked its food restrictions.
People should always consult with a physician before beginning any weight-loss program. This is crucial before starting phase 1, especially for women who are pregnant or breastfeeding. People should carefully read the ingredient and nutrition labels on all processed products to ensure that the product is in line with their dietary wishes.
The South Beach diet is not a completely low-carbohydrate diet. Phase 1 is, but the other phases allow the gradual introduction of carbohydrates. In Phase 3, a person might eat up to 140 grams of carbohydrates a day, which would be close to 30% of daily calories on a 2,000-calorie diet. The traditional dietician community has disparaged phase 1 of the South Beach diet for being excessively restrictive and too low in carbohydrates but praised it for not allowing unlimited amounts of saturated fat. On the other hand, proponents of low-carbohydrate, high-fat diets warn that adding back too many carbohydrates presents the risk of gaining back the lost weight. Dr. Tim Noakes suggests that some individuals with insulin resistance are very sensitive to carbohydrates and will suffer high blood sugars and high levels of insulin even after eating very small amounts of carbohydrates. Dr. William Davis has suggested that the feeling of well-being some people experience on phase 1 is due to their elimination of wheat products and that they can safely leave those out of their diet for good.
The U.S. News & World Report's panel and a review of the research in July 2017 indicated no serious short-term risks or side effects related to the South Beach diet. The Mayo Clinic called the weight-loss plan “generally safe” if people adhered to the plan as described in the official South Beach books and website.
Research published in JAMA in 2014 found that there was not much difference among several tested diets in weight loss, concluding that patients should choose the diet that they find easiest to comply with. People who have tried the South Beach diet report that it works well, and many report successfully overcoming their insulin resistance. It is overall less restrictive than true low-carbohydrate approaches, which is appealing to many people who want to keep favorite foods in their lives.
The lifetime maintenance phase of the South Beach diet generally falls in line with the U.S. government's dietary recommendations, which include consuming a variety of fruits and vegetables, whole grains, lean proteins, and low-fat dairy products, while limiting saturated and trans fats, added sugars, and sodium. The federal guidelines also encourage people to be physically active. Regular exercise is generally accepted as an excellent way of improving health, reducing the risk of disease, and managing weight. Cardiology research from 2015 suggested that high-carbohydrate diets increase the risk of heart disease, while the South Beach diet's approach to saturated fats might help reduce the risk of heart disease.
See also Glycemic index diets ; High-fat, lowcarb diets ; High-protein diet .
Agatston, Arthur. The South Beach Diet Super Quick Cookbook: 200 Easy Solutions for Everyday Meals. Emmaus, PA: Rodale, 2010.
Agatston, Arthur. The South Beach Diet Supercharged: Faster Weight Loss and Better Health for Life. New York: Rodale, 2008.
Agatston, Arthur. The South Beach Heart Program: The 4-Step Plan That Can Save Your Life. Emmaus, PA: Rodale, 2006.
Agatston, Arthur, with Joseph Signorile. The South Beach Diet: The Delicious, Doctor-Designed, Foolproof Plan for Fast and Healthy Weight Loss. Emmaus, PA: Rodale, 2003.
Fung, Jason, and Timothy Noakes. The Obesity Code: Unlocking the Secrets of Weight Loss. Vancouver, Canada: Greystone Books, 2016.
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Academy of Nutrition and Dietetics, 120 South Riverside Plz., Ste. 2000, Chicago, IL, 60606-6995, (312) 899-0040, (800) 877-1600, firstname.lastname@example.org, http://www.eatright.org .
Tish Davidson, AM
Revised by Amy Hackney Blackwell, PhD