Weighing in on the South Beach Diet
Should you try the diet of the moment?
Here’s what you need to know.
You don’t have to live in the tony Miami neighborhood
of South Beach to have heard about—and possibly even tried—The
South Beach Diet. At press time, it had been on the New
York Times list of hardcover advice books for over a year
and was among the top 10 books sold at amazon.com. But will this
diet plan work for you?
In a nutshell, the South Beach Diet is a reduced-carbohydrate
meal plan that is set up in three phases. Phase one, the most
restrictive part of the plan, lasts two weeks and is designed
to initiate rapid weight loss by eliminating most carbohydrates.
Dieters are advised to go back on phase one of the plan if they
experience any setbacks to weight loss, such as overindulging
on vacation. Phase two allows dieters to resume eating more carbohydrates,
including whole-grain breads and cereals, sweet potatoes, and
most fruits, but limits the portion sizes of these foods. Phase
three is the maintenance part of the meal plan and is supposed
to be more flexible than the other two phases.
The premise behind the book is that overindulging in highly
processed carbohydrates raises blood glucose levels, leading
to surges in insulin that cause sugar cravings and weight gain.
By limiting such carbohydrates, the South Beach Diet suggests
that you can virtually eliminate cravings for carbohydrates and
sugary sweets and lose weight—all without counting calories
or measuring portion sizes.
Moreover, The South Beach Diet author, Dr. Agatston,
claims that avoiding so-called “bad” carbohydrates
such as white bread and sweets in favor of “good” ones
like whole grains, fruits, and vegetables will cure insulin resistance
and decrease your risk of coronary heart disease.
A Day in South Beach
Despite Dr. Agatston’s claims that the South Beach Diet “is
distinguished by the absence of calorie counts; percentage counts
of fats, carbs, and proteins; or even rules about portion size,” the
meal plans involve recipes that state portion sizes, and portions
are given for most items on the menus. Therefore, the diet ultimately
restricts calories. In fact, a calorie analysis of day one on
phases one and two reveals that a dieter who strictly follows
the meal plan would consume about 1,500 calories a day; day one
on phase three—the maintenance part of the plan—contains
about 2,000 calories. Certainly, many people could lose weight
on 1,500 calories a day and maintain their weight consuming 2,000
Weight and Insulin Resistance
The South Beach Diet suggests that overeating highly processed
carbohydrates contributes to weight gain, which leads to insulin
resistance. Though it’s true that overeating causes weight
gain, the source of the calories doesn’t affect weight.
In addition, the book oversimplifies the cause of insulin resistance.
Although obesity is the more common cause of insulin resistance,
genetic factors, diet, physical inactivity, cigarette smoking,
and older age contribute to it as well.
The Glycemic Index
The meal plan in the South Beach Diet is built upon the glycemic
index, which assigns each food a number based on the rise in
blood glucose it produces during the first two hours after eating
it compared with the rise triggered by eating an equivalent amount
of carbohydrate in a standard food like white bread.
The South Beach Diet, particularly in phase one, calls for choosing
foods that are low on the glycemic index in order to avoid surges
in blood glucose. Moreover, the book suggests that consuming
low-glycemic foods will curb your appetite and minimize your
cravings. Again, this message is oversimplified.
According to the American Diabetes Association, the amount of
carbohydrate consumed each day is more important in determining
the body’s glucose response than the glycemic index of
each individual carbohydrate.
Another problem with the index is that it is not practical.
The index rates only single foods eaten individually, which is
not the way people eat. Finally, the effect of a food on blood
glucose levels can vary depending on whether a particular food
is cooked or eaten in combination with other foods, and what
the blood glucose level is before eating.
Furthermore, many nutritious foods, such as corn, carrots, and
raisins, are high on the glycemic index, but that doesn’t
mean they need to be eliminated in order to stay healthy or lose
The Bottom Line
Despite some of the problems mentioned above, the South Beach
Diet does make some good points, particularly about choosing
whole-grain foods, fruits, and vegetables over processed carbohydrates.
As Agatston points out, these foods contain fiber, which helps
fill you up, but are naturally low in fat and calories. Furthermore,
unlike Atkins—who revolutionized low-carbohydrate eating—Agatston
focuses on lean meats, low-fat dairy products, and healthy sources
of fats, like nuts and fish.
Though phase one severely limits carbohydrates, several clinical
trials over the last few years have shown that dieters lose weight
on these types of meal plans—at least in the short term.
It’s possible that the initial weight loss will motivate
people to remain on the diet. Phase two calls for filling up
on lots of fruits and vegetables, along with lean meats and reduced
fat cheeses, which is a reasonable way to lose weight. Finally,
phase three allows for more carbohydrates from fruits and whole
grains, which is a sensible plan for maintenance. Though South
Beach does allow low-fat dairy products, most adults could benefit
from additional servings to meet their calcium needs.
Of course, in addition to reducing calories, exercise is a critical
component of a weight loss program. Though Dr. Agatston claims
the South Beach Diet doesn’t depend on exercise in order
to work, studies have shown that people who exercise are more
likely to maintain their weight loss.