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.

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 it. 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, the attempt to reduce the risk of heart disease actually increased it.

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.

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.

"Good fats" vs "bad fats"
Given that South Beach Diet was designed by a cardiologist, it should be no surprise that it eliminates trans-fats and discourages saturated fats. Although foods rich in these "bad fats" do not contribute to the hunger cycle, they do contribute to LDL cholesterol and heart disease. The South Beach Diet replaces them with foods rich in unsaturated fats and omega-3 fatty acid which contribute to HDL cholesterol and provide other health benefits. 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 purpose is to eliminate the hunger cycle and is expected to result in significant weight loss. "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. Instead, the dieter is expected to understand the basic principles of the diet and live by the principles.

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 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 their source. 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
- Most criticism of the South Beach Diet lumps it (fairly or not) with "low-carb" and other "fad diets" and dismisses the entire set as "snake oil".

- 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 noted that 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. However, she warns that 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.

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