South Beach Diet

The South Beach Diet is a diet plan designed by cardiologist Arthur Agatston and dietician Marie Almon as an alternative to low-fat approaches such as the Ornish Diet and the Pritikin Diet advocated by the American Heart Association in the 1980s. Although the original purpose of the diet was to prevent heart disease in Dr. Agatston's own patients, in the early 2000s, word of the diet spread and quickly gained popularity as a means to lose weight.

The term "South Beach Diet" is a trademark of South Beach Diet Trademark Limited Partnership. A book, The South Beach Diet, was published by Rodale Books in 2005.

History and theory
While Agatston accepted the prevailing wisdom among cardiologists that a low-fat diet would reduce cholesterol and prevent heart disease, he found that, in practice, patients had a difficult time sticking to the diet. To explain this failure, he turned to the scientific work with insulin resistance which led David J. Jenkins to develop the glycemic index in the early 1980s. When sugar enters the bloodstream, the pancreas secretes insulin which triggers cells to absorb the sugar. Many years of introducing quick bursts of sugar would eventually result in cells becoming resistant to insulin. This resistance would leave sugar in the bloodstream longer which would then cause the pancreas to release even more insulin. This excess insulin would eventually drive blood sugar below normal levels. Jenkins (and others) discovered that, in addition to potentially causing diabetes, this effect would also produce cycles of hunger. Excess sugar consumption led to excess insulin, which led to low blood sugar, which led to hunger pangs, which led to the consumption of more sugar.

Agatston postulated that patients on low-fat diets were eating no less food than they had been before they started the diet. They simply had compensated for the fat by consuming additional sugar and simple carbohydrates (which are rapidly reduced to sugar by the digestion process). This led to the cycles of hunger that Jenkins had described. As a result of this hunger, patients were consuming excess calories and gaining weight, ironically defeating their attempt to reduce the risk of heart disease.

Agatston was aware of the low-carbohydrate diet popularized by Robert Atkins in the 1970s, but he feared that this diet would lead to too few carbohydrates, too much saturated fat, too little fiber, and a number of maladies including an increased risk of heart disease. However, note that the link between dietary fat and blood cholesterol has been heavily questioned.

The diet
The South Beach Diet is relatively simple in principle. It replaces "bad carbs" and "bad fats" with "good carbs" and "good fats."

"Good carbs" vs "bad carbs"
According to Agatston, hunger cycles are triggered not by carbohydrates in general, but by carbohydrate-rich foods that the body digests quickly, creating a spike in blood sugar. Such foods include the heavily refined sugars and grains that make up a large part of the typical Western diet. The South Beach Diet eliminates these carbohydrate sources in favor of relatively unprocessed foods such as vegetables, beans, and whole grains. Carbohydrate sources are considered "good" only if they have a low glycemic index.

"Good fats" vs "bad fats"
The South Beach Diet eliminates trans-fats and discourages saturated fats, replacing them with foods rich in unsaturated fats and omega-3 fatty acid. Specifically, the diet excludes the fatty portions of red meat and poultry, replacing them with lean meats, nuts, and oily fish.

Phases
Agatston divides the South Beach Diet into three phases, each progressively becoming more liberal. "Phase 1" lasts for the first two weeks of the diet. It eliminates all sugars, processed carbohydrates, fruits, and some higher-glycemic vegetables as well. Its main purpose is to get rid of the hunger cycle. "Phase 2" continues as long as the dieter wishes to lose weight. It re-introduces most fruits and vegetables and some whole grains as well. "Phase 3" is the maintenance phase and lasts for life. There is no specific list of permitted and prohibited foods. Dieters are expected to take what they have learned and apply it to their life without any guidance.

Scientific studies
A 2004 study of the South Beach Diet by diet developer Agatston, et al., reviewed a 1998–1999 trial completed by 54 participants over the course of a year. A 2005 study of the South Beach Diet conducted by Kraft Foods, makers of the South Beach Diet food line, was completed by 69 subjects over the course of just under three months. Both studies showed favorable results for the groups using the South Beach Diet.

Confusion with "low-carb" diets
Many sources place the South Beach Diet on lists of "low carb" diets such as the Atkins Diet. While the South Beach diet does prohibit foods rich in simple carbohydrates such as white bread, white potatoes and white rice, it does not require dieters to forgo carbohydrates entirely or even measure their intake. Instead, it focuses on the "glycemic impact" (short term change in blood glucose) of foods. Many vegetables are permitted even in phase 1. Complex, fiber-rich carbohydrate sources such as brown rice and 100% whole grain bread are permitted during phase 2. Agatston has tried to distance the South Beach Diet from "low carb" approaches: "It is my purpose to teach neither low-fat nor low-carb. I want you to learn to choose the right fats and the right carbs." In fact, there is a vegetarian variation of the South Beach Diet which is relatively high in carbohydrates.

Criticism

 * In 2006, the Journal of General Internal Medicine published an evaluation of 42 nutrition and health claims made by the South Beach Diet book. The report found that only 33% of the claims made in the book could be confirmed by findings in the scientific literature, while 17% were not supported. Another 43% yielded "both supported and not supported" results, and 3 claims had no support for or against.
 * Dr. Elizabeth Mayer-Davis, a diabetes researcher, questions the validity of the glycemic index, on which the diet is based.
 * Cindy Moore, RD, a director of nutrition therapy at Cleveland Clinic and a former spokeswoman for the American Dietetic Association claimed that although the diet meets the important criteria for a healthy diet: it emphasizes vegetables, fruits, whole grains, and lean protein while not omitting any major food group, phase 1 can throw the body's electrolyte balance off because most of the weight loss is water weight.
 * Anheuser-Busch produced a press release disputing Agatston's claim that beer has a high glycemic index due to its maltose content.

South Beach Living packaged foods
In 2004, Kraft Foods licensed the South Beach Diet trademark for use on a line of packaged foods called South Beach Diet. These have been renamed South Beach Living. These products are designed to meet the requirements of the diet.