South Beach Glycemic Diet

The South Beach Diet is based mostly on the glycemic index, which measures how quickly specific carbohydrates raise your body's blood sugar. Dr. Arthur Agatston, the founder of the South Beach Diet, believes that obesity is caused by rapid rises and plunges in blood sugar that create cravings for "quick carbohydrate fixes." Foods with high glycemic index scores are banned from Phase I of the South Beach Diet and should be eaten in limited quantities afterward, writes Agatston.

History

The U.S. government and a consensus of health-related organizations such as the American Heart Association have recommended since the 1970s that Americans eat more high-carbohydrate foods, such as breads, cereals, pastas and rice, and fewer high-fat foods, such as meat and cheeses. The U.S. Department of Agriculture (USDA), for example, wants about 55 percent of your calories to come from carbohydrates, about 29 percent from fat and approximately 18 percent from protein. The USDA's recommendation "has caused the fattening of America," writes Agatston.

Theory

The glycemic index was introduced by Dr. David Jenkins in the early 1980s and gained credibility as the Atkins Diet became popular. Jenkins discovered that the fat and protein in foods caused a negligible rise in blood sugar and did not cause body fat. Rapid blood sugar increases spur large insulin production increases that, in turn, cause rapid plunges in blood sugar, Agatston writes. Low blood sugar levels spur cravings for food and "more fat, more insulin resistance, more hunger and more weight gain--a vicious cycle."

Glycemic Scores

Foods with a glycemic index score of 70 or higher are considered high glycemic index foods, and foods with a score of 55 or lower are low glycemic index foods, according to the Harvard School of Public Health. Many low-fat foods recommended by the USDA have very high scores. They include starchy vegetables, such as carrots and potatoes, tropical fruits, such as bananas and pineapples, and most breads, cereals and pastas. Many high-fat desserts also have high glycemic index scores.

Body Chemistry

You cannot eat bread, fruit, rice or pasta, even when they have low glycemic index scores, nor vegetables with high glycemic index scores during the first two weeks of the South Beach Diet. Eliminating most carbohydrates changes your body chemistry so you will no longer crave carbohydrates, and your cravings "switch" will remain off if you eat mostly low glycemic index foods for the rest of your life, Agatston writes.

Good Carbohydrates

The South Beach Diet relies on "the right fats and the right carbs," according to Agatston. The "right fats" means that foods high in saturated fats aren't part of the diet, although they have low glycemic index scores and the Atkins Diet encourages them. The "right carbs" have a lot of fiber that "delay the absorption of sugars and starches." High-fiber foods often have low glycemic index scores. They include soybeans, lentils, kidney beans, berries, cherries, grapefruit, asparagus, beets, Brussels sprouts, celery, green beans, lettuce, snow peas, squash and tomatoes.