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South Beach Diet

By Mayo Clinic staff

Definition

The South Beach Diet is a popular weight-loss diet created in 2003 by cardiologist Arthur Agatston and outlined in his best-selling book, "The South Beach Diet: The Delicious, Doctor-Designed, Foolproof Plan for Fast and Healthy Weight Loss." The South Beach Diet is a commercial weight-loss diet, not a medical diet prescribed by your doctor.

The South Beach Diet, which is named after a glamorous area of Miami, claims that it is neither a low-carbohydrate diet nor a low-fat diet, and it doesn't require carb counting. The South Beach Diet, however, is lower in carbohydrates and higher in protein and healthy fats than is a typical eating plan. Most low-carb diets are those that limit your carbs to no more than 20 percent of your daily calorie intake. On the South Beach Diet, you can get as much as 28 percent of your daily calories from carbohydrates. Because of this, the South Beach Diet is sometimes called a modified low-carbohydrate diet.

Purpose

The purpose of the South Beach Diet is to change the overall balance of the foods you eat to encourage weight loss and a healthy lifestyle.

Why you might follow the South Beach Diet
You might choose to follow the South Beach Diet because you:

  • Enjoy the types and amounts of food featured in the diet
  • Believe that a diet that restricts certain carbs and fats will help you lose weight quickly or easily
  • Think that following this diet will help you achieve overall healthier eating habits
  • Think that you can stick with this diet for the long term
  • Like the related South Beach Diet products, such as cookbooks and diet foods
  • Have friends who are doing the South Beach Diet

Check with your doctor or health care provider before starting any weight-loss diet, especially if you have any health concerns.

Diet details

The South Beach Diet claims that its balance of the "right" carbs and the "right" fats makes it a nutrient-dense, fiber-rich diet that you can follow for a lifetime of healthy eating. The South Beach Diet claims that it'll teach you about eliminating "bad" carbs from your diet. It defines bad carbs as those with a high glycemic index. Foods with a high glycemic index tend to increase your blood sugar faster, higher and longer than do foods with a lower index. Some evidence suggests that this increase in blood sugar can boost your appetite, leading to increased eating and weight gain and possibly diabetes, which can all contribute to cardiovascular disease.

The South Beach Diet also teaches you about the different kinds of fats and encourages you to limit unhealthy trans fats and saturated fats, while eating more foods with healthier monounsaturated fats. The South Beach Diet emphasizes the benefits of fiber and whole grains, encouraging you to include lots of "colorful" fruits and vegetables in your eating plan.

Phases of the South Beach Diet
The South Beach Diet has three phases:

  • Phase 1. In this strict initial two-week phase, you cut out almost all carbohydrates from your diet. Instead of getting the recommended 45 to 65 percent of your daily calories from carbohydrates, you get only about 10 percent. You focus on eating meats, seafood, vegetables, eggs, cheese, nuts, salads and healthy fats and oils. You cut out all fruit, as well as bread, rice, potatoes, pasta, baked goods, sweets and alcohol. Carbohydrate cravings are supposed to stop.
  • Phase 2. You begin adding back some of the previously banned foods, including certain carbs. Carbs account for about 27 percent of your daily calories. You stay in this phase until you reach your goal weight.
  • Phase 3. This is a maintenance phase meant to be a healthy way to eat for life, with "normal" foods in "normal" serving sizes. About 28 percent of your daily calories come from carbohydrates. If you gain weight, you start over with phase 1.

A typical day's menu on the South Beach Diet
Here's a look at what you might eat during a typical day on phase 1 of the South Beach Diet, according to the South Beach Diet Web site:

  • Breakfast. Breakfast might be a veggie quiche filled with cheese, spinach and other fresh vegetables. You can have a cup of coffee or tea, or a glass of tomato juice.
  • Lunch. One lunch option is grilled chicken salad on a bed of romaine with balsamic vinaigrette. You can have iced tea, diet soda or sparkling water.
  • Dinner. Dinner may feature spicy seared tuna with grilled vegetables and a salad.
  • Dessert. The diet encourages you to eat a dessert, such as chilled espresso custard.
  • Snacks. You're allowed two snacks a day, such as certain cheeses, turkey roll-ups, hummus and celery, tomatoes and cottage cheese, or mixed nuts.

Results

Weight loss
The claim: The South Beach Diet claims that you'll lose 8 to 13 pounds in the two-week period that you're on phase 1. It also claims that most of the weight will be shed from your midsection. In phase 2, it claims that you'll likely lose 1 to 2 pounds a week.

The reality: Use of lower carbohydrate diets like the South Beach Diet to lose weight remains controversial among health professionals. Most people can lose weight on almost any diet — in the short term. But over the long term, low-carb or modified-carb diets are no more effective than are standard high-carbohydrate diets. Most important to weight loss is how many calories you take in and how many calories you burn off. Traditional recommendations for weight loss advise losing 1 to 2 pounds a week by following a diet that reduces fat and calories and emphasizes complex carbohydrates. Losing a large amount of weight rapidly could indicate that you're losing water weight or lean tissue, rather than fat.

Health benefits
The claim: The South Beach Diet, while mainly directed at weight loss, claims it can "save your life" by improving your cardiovascular health.

The reality: Lower carbohydrate diets with healthy fats may improve your blood cholesterol levels, at least in the short term. But no long-term, randomized controlled clinical trials have measured the health outcomes of the South Beach Diet. Nor have there been such studies of the overall health or cardiovascular benefits of following a low-glycemic-index diet. Many factors other than just what you eat influence your blood sugar level, including your age and weight, physical activity, medications, how food is prepared, and portion size.

Exercise
The claim: The South Beach Diet doesn't emphasize physical activity as a part of your weight-loss regimen or healthy lifestyle. It claims that you'll lose weight regardless of your physical activity level, but that you'll lose more weight, and lose it faster, if you do get regular exercise. The South Beach Diet, which has evolved since it was first created, does recommend taking a 20-minute walk each day to boost metabolism.

The reality: It's true that weight loss depends on burning more calories than you take in, and that cutting back on total calories consumed seems to be more important for weight loss than burning calories through exercise. However, regular physical activity is vital to prevent regaining the weight you've lost. In addition, physical activity has many health benefits. According to the Department of Health and Human Services, as a general goal, include at least 30 minutes of physical activity in your daily routine. If you want to lose weight or meet specific fitness goals, you may need to increase your activity even more. If you can't set aside time for a longer workout, try 10-minute chunks of activity throughout the day. Remember, the more active you are, the greater the benefits.

Risks

It's not known what risks, if any, the South Beach Diet may pose to your health, especially over the long term. It's possible that restricting carbohydrates to less than 20 grams a day — the recommendation for phase 1 of the South Beach Diet — can result in ketoacidosis. Ketoacidosis occurs when you don't have enough sugar (glucose) for energy, so your body breaks down stored fat, causing unhealthy levels of ketones and acid to build up in your body. Left untreated, ketoacidosis can cause stupor, coma and even death.

There are some other risks that may occur when you start any commercial weight-loss diet:

  • If you skip a face-to-face evaluation with your health care provider, you may be unaware of important medical concerns.
  • The diet isn't tailored to your specific situation, including your weight-loss goals and any health conditions you might have
  • The very restrictive menu in phase 1 of the South Beach Diet may cause you to give up on your weight-loss goals.
References
  1. Goff SL, et al. Nutrition and weight loss information in a popular diet book: Is it fact, fiction, or something in between? Journal of General Internal Medicine. 2006;21:769.
  2. Yungsheng MA, et al. A dietary quality comparison of popular weight-loss plans. Journal of the American Dietetic Association. 2007;107:1786.
  3. How does the diet work? The South Beach Diet Online. http://secure.agoramedia.com/sbd2/learn/phases.html. Accessed Jan. 2, 2009.
  4. Baron M. Fighting obesity. Health Care Food & Nutrition Focus. 2004;21:1.
  5. Chalasani S, et al. South Beach Diet associated ketoacidosis: A case report. Journal of Medical Case Reports. 2008;2:45.
  6. Rutten LF, et al. Awareness, use, and perceptions of low-carbohydrate diets. Preventing Chronic Disease. 2008;5(4).
  7. Last AR, et al. Low-carbohydrate diets. American Family Physician. 2006;73:1942.
  8. What will you eat? The South Beach Diet Online. http://secure.agoramedia.com/sbd2/learn/food.html. Accessed Jan. 2, 2009.
  9. Malik VS, et al. Popular weight-loss diets: From evidence to practice. Nature Clinical Practice Cardiovascular Medicine. 2007;4:34.
  10. Why is the South Beach Diet successful (press release)? New York, N.Y.: South Beach Diet; 2007. http://www.southbeachdiet.com/public/diet-press/Why%20Is%20the%20South%20Beach%20Diet%20Successful.pdf. Accessed Jan. 20, 2009.
  11. Aude YW, et al. The National Cholesterol Education Program Diet vs a diet lower in carbohydrates and higher in protein and monounsaturated fat. Archives of Internal Medicine. 2004;164:2141.
  12. Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). Washington, D.C.: The National Academies Press; 2005.
  13. Agatston AS. The South Beach Diet: The Delicious, Doctor-Designed, Foolproof Plan for Fast and Healthy Weight Loss. Emmaus, Pa.: Rodale; 2003.
  14. 2008 physical activity guidelines for Americans. U.S. Department of Health and Human Services. http://www.health.gov/paguidelines/pdf/paguide.pdf. Accessed Feb. 6, 2009.
  15. Hensrud DD (expert opinion). Mayo Clinic, Rochester, Minn. Feb. 26, 2009.

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April 18, 2009

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