Low-carb diets are all the rage – but do they work?

Low carb dietsFor years, many dieters have believed that a low fat diet — including pasta, breads, and even low-fat cookies — is they key to achieving successful weight loss. But if Dr. Barry Sears, creator of the Zone diet, and his fellow low-carbohydrate proponents are correct, then there are a lot of mistaken dieters out there.

When Sears’ book “The Zone” was released in 1990’s, most popular diets of the time advocated eating lots of carbohydrates like vegetables and fruits, and cutting out proteins and fats like red meat and butter. However, Sears’s book resurrected the idea of the high protein, low carbohydrate diet, which was first popularized by Dr. Robert Atkins in the 1970s. There are now a multitude of variations on these low carbohydrate diets, including Sugarbusters, Protein Power and Get Skinny on Fabulous Foods.

The Zone advocates eating carbohydrates, protein, and fat in a 40-30-30 ratio. The Zone is supposed to work because it’s tailored to a person’s lean body mass (total weight minus weight of fat) by adjusting the amount of food consumed according to a specific formula Sears developed.

In theory, the Zone optimizes the body’s performance by eliminating quick fluctuations in insulin levels due to the consumption of certain foods. Insulin removes sugar from the blood and stores it as fat; by suppressing large fluctuations in insulin, the amount of fat the body stores is theoretically reduced. Most of the low carbohydrate diets follow some variation on Sears’ reasoning that insulin is “the fat molecule”.

Jim Benson, MD, an endocrinologist at Virginia Mason Hospital in Seattle, takes issue with the depiction of insulin as the reason for weight gain.

“Proponents of these diets make insulin sound dangerous,” Benson says. It’s not — insulin is a naturally created hormone.

“The Zone” includes a list of foods optimal for the Zone diet, and tell readers which foods should be consumed infrequently. He also simplifies the 40-30-30 ratio in a block system. Using Sears’ formulas, you can determine the number of blocks appropriate for your weight and athletic activity, and then look in the back of the book to determine how much of a certain food is equivalent to one block.

The Atkins diet is an extreme variation of a low carbohydrate diet. While the Zone warns against eating high fat meats products like bacon and sausage, the Atkins diet says that as long as a high protein, low carbohydrate regimen is followed, all meats are acceptable. The theory behind the diet is similar to that of the Zone: carbohydrates cause rapid increases in insulin, which cause the body to convert sugar to fat. The Atkin’s diet removes sugar as an energy source for the body, and replaces it with fat.

Food PyramidAccording to Atkins, when the body breaks down fat for energy, it releases ketones, which act as a hunger suppressant. Therefore, even though people are eating more fat, their appetites gradually decrease. However, the process of releasing ketones from fat, called ketosis, can cause dehydration, nausea and a number of other symptoms that can negatively affect your health.

Although the authors of low carbohydrate diets claim to have scientific proof of their effectiveness, there are many doctors and nutritionists who criticize these diets as unhealthy and even dangerous. The American Dietetic Association called the Atkins Diet a nightmare, and most health organizations recommend a much higher level of carbohydrate consumption than any low carbohydrate diet offers.

“Like most diets, the only reason [low carb diets] are successful is because they are hypocaloric. There’s nothing magic versus any other diet, whether low fat or low carb,” Benson says.

With low-carb diets, especially in the case of the Atkins Diet, some critics believe the initial rapid weight loss is a result of dehydration due to ketosis. Once the dieter is sufficiently dehydrated, weight gain will occur as the body stores large amounts of fat. There are also concerns that the too much protein overworks and damages the kidneys; that increased fat consumption is linked to heart disease; and that valuable vitamins and minerals found only in fruits and vegetables are absent in the Atkins diet.

Unfortunately, no long-term research on low carbohydrate diets exists, so it is impossible to weigh costs and benefits definitively.

Dr. Robert Kushner, the director of the Wellness Center at Northwestern University, urges patients to consider their diet options carefully. “Think about it, and say does this make sense? Does eating a diet high in fat and high in protein really make sense? Is it too good to be true? Yes, it is too good to be true.”

Still, there are many who have found great success with these diets, despite warnings from nutritionists.

Ultimately, the success of any diet depends on the individual. A low carbohydrate diet is well suited to your metabolism, or the opposite could be true. Make sure you consult a doctor before beginning any serious diet program. And no matter what diet you are on, get regular exercise and take care to meet all your vitamin and mineral needs.

Alex Smith likes to consume sugar whenever he can.

Additional Sources:

CNN Survey: Many opt for high protein, low carb diets

Image courtesy: Time Magazine