Weight Loss Hype in the Zone

---

High carbohydrate diets make athletes fat and impair performance.

Sounds hard to believe? It is.

Yet, that's what Barry Sears, Ph.D., claims in his hot-selling book, Enter the Zone. Sears promises that you can "lose weight permanently" by following "exceptionally easy" rules. In the process you can also reach a near-euphoric state of maximum physical and psychological performance. In case these benefits aren't enough, Enter the Zone also claims that the Zone diet can treat heart disease, cancer, diabetes, and even AIDS.

What's the bottom line here? Does a high carbohydrate athletic diet make you fat and hurt your performance? Has Sears found a better way to eat?

No.

As a registered dietitian, exercise physiologist, and endurance athlete with over 16 years of experience studying and practicing performance nutrition, I'll tell you why.

Enter the Zone maintains that carbohydrates are bad because they raise your blood sugar level and cause the release of the hormone insulin -- a supposed monster hormone. Actually, insulin is a essential hormone that helps transfer sugar or glucose from the bloodstream to the body's cells, where it's used to fuel all of our activities. However, Enter the Zone claims that when insulin levels go up, "you're stuck in carbohydrate hell" and way out of the Zone -- the "state in which your body and mind work together at their ultimate best."

According to Sears, the problem is that insulin causes the body to make "bad" eicosanoids -- hormone-like substances that the body makes from certain unsaturated fatty acids. Enter the Zone claims that "bad" eicosanoids cause most major health problems, such as heart disease, cancer, arthritis, and even depression. "Bad" eicosanoids also supposedly harm your performance by reducing oxygen transfer to the cells, lowering blood glucose levels, and interfering with body fat usage.

Reality check number one -- eicosanoids don't cause disease or impair athletic performance.

The claim that eicosanoids are all-powerful is ridiculous -- the body's physiology just isn't that simple. There's also no evidence that insulin even makes "bad" eicosanoids.

According to Sears, insulin not only hurts your health and performance, it makes it hard for you to stay, or become, thin. Basically, Enter the Zone treats insulin as the hormone that makes you fat. Supposedly, insulin does this by taking your high-carbohydrate food and storing it as fat rather than allowing the body to use it for energy.

Reality check number two -- insulin doesn't make you fat.

Like it or not, what you weigh depends on how many calories you take in compared to how many you burn off. Eating a high percentage of calories from carbohydrate doesn't make you fat -- you must eat too many calories relative to your needs for insulin to lay down fat. However, your body would rather burn carbohydrate for energy than store it as fat.

Unfortunately, not paying attention to calories gets alot of people into trouble. When health professionals encourage people to eat more carbohydrate and less fat, many folks get the wrong idea. They think they can eat as much high-carbohydrate food as desired, as long as the food is fat-free. The result -- these people can't lose weight or even gain weight because they eat too many calories in the form of high-carbohydrate, low-fat sweets as well as extra large portions of starches such as bread and pasta. Instead of blaming their forks, they blame the carbohydrate.

The moral of this story -- active people can't eat an unlimited amount of carbohydrate by cutting down on their fat intake. Cutting back on dietary fat does reduce total calories more than cutting back on dietary carbohydrate, because fat supplies more than twice the calories by weight. Fat is also more likely to be stored as body fat than is carbohydrate. However, if you cut back on fat calories but add them back in the form of carbohydrate calories, you're not going to lose weight. It's a simple matter of energy balance whether you're an athlete or a couch potato.

Even though carbohydrate and insulin are not villains, Enter the Zone recommends a complicated, carbohydrate-restricted diet. The book tells you to treat food as a drug, to "eat food in a controlled fashion and in the proper proportions, as if it were an intravenous drip." Specifically, that means eating exactly 40% of calories as carbohydrate, 30% as protein, and 30% as fat at each meal and snack. Supposedly, this revolutionary diet will make you thinner, healthier, and a better athlete. What it really does it take the fun out of eating. Almost all professional health groups in the country recommend 55 to 60% calories as carbohydrate, 10-15% as protein, and the remainder as fat. And not every time you sit down to eat.

Reality check number three -- there's nothing magical about why the Zone diet promotes weight loss -- it's simply an extremely low calorie diet.

Enter the Zone attempts to disguise this fact by having you count fancy protein and carbohydrate blocks instead of calories. Although the book says "don't focus on calories," the Zone diet provides only 800-1,200 calories a day for the average person.

You'll lose weight on the Zone diet because of the severe caloric restriction -- not because of what is supposedly happening to your insulin levels or eicosanoids. You'll lose something else, too, eventually. Your performance. You can't train or compete well for very long on such a low calorie, low-carbohydrate diet. You need to eat enough calories and carbohydrate to maintain your muscle glycogen levels -- the favored fuel for exercise. The Zone diet supplies about half the number of calories I recommend for an active person trying to lose weight. Follow this diet and the only zone you'll enter is the twilight zone of near starvation and impaired performance.

Contrary to what Enter the Zone claims, eating a high carbohydrate meal one to four hours before exercise improves performance by "topping off" your glycogen stores. Consuming carbohydrate during workouts lasting longer than an hour aids endurance by providing glucose for your muscles to use when they're running out of glycogen. And, taking in carbohydrate right after hard training increases muscle glycogen storage and helps improve your recovery time.

No dietary regimen can change your body's preference for carbohydrates over fats as fuel or help you burn more fat. Carbohydrate, not fat, is the preferred fuel for exercise at or above 70% of aerobic capacity -- the intensity at which most people train and compete. And, as far gradual loss of body fat, that comes from burning more calories during exercise than you take in, not from some special dietary ratio.

The bottom line -- you don't need to follow this rigid diet for weight loss, optimum performance, or health.

Ellen Coleman, RD, MA, MPH
ellen@cruciblefitness.com