To those of us in the swimming world, the name Barry Sears, Ph.D. is not new. We first heard about him when Richard Quick and Skip Kenney, the women's and men's swim coaches at Stanford, started singing his praises back in 1992, around the time of the Barcelona Olympics. This year his book The Zone: A Dietary Road Map (published by ReganBooks, 1995) has been on the best seller list for more than sixteen weeks. Numerous articles about him and his diet have appeared in magazines. It seems that now would be an appropriate time for me to write a review of his book for Swimmer's Source!

First of all I'd like to state that I basically think that this diet is safe, in contrast to some of the all-protein-no-carbohydrate diets that are currently being touted. I do not think that most people following this diet will find it harmful, as it basically includes all of the food groups.

Secondly, I'd like to say from the outset, that I am always skeptical when someone comes out with a new diet, promising weight-loss and improved athletic performance. I am even more wary when that individual has an entire product line supporting the diet.

The premise of the "zone diet" is to have each meal consistendy maintain the following percentages: carbohydrates 40%, proteins 30%, fats 30%. The protein to carbohydrate ratio should be 0.75. He says that the size of the protein-rich food and the carbohydrate should be roughly equal when you look at them on your plate. He goes into more detail on what he considers more and less favorable carboydrates. More favorable carbohydrates include many fruits and vegetables, while less favorable ones include potatos most fruit juices, and all grains and breads.

The reasoning behind this diet has to do with the hormones insulin, glucagon, and the eicasanoids (which include the prostaglandins). In a nutshell: the pancreas releases insulin in response to sugar/carbohydrates (carbohydrates are made up of sugars). Insulin is responsible for the uptake of sugar by the cells. The sugar that can neither be used nor stored as glycogen, is then converted to and stored as fat.Glucagon is also released by the pancreas, but in response to protein. It's function is to mobilize stored sugars (glycogen). Prostaglandins are "local" hormones that are manufactured at the site they are to affect. The body manufactures these hormones from essential fatty acids. All of this information can be found in any newer edition human physiology or endocrinology textbook.

From this information, Dr Sears goes on to hypothesize that eating large amounts of carbohydrates, especially the unfavorable ones, causes the body to release an overabundance of insulin. As a result, much of the carhohydrate is converted to and stored as fat. This insulin response also leads to sluggishness and fatigue. If one eats the "proper balance" of carbohydrate and protein, the right amount of insolin and glucagon are released and voila, no more fat storage problem, and one can lose weight. As a side note, he also recommends one horn about 2,000 calories per week, which is the equivalent of brisk walking for one hour six days per week.

The other part of his hypothesis involves the interaction between insulin, glucagon, and the essential fatty acids and the production of "good" prostaglandins. Basically, following his zone-favorable diet insures an abundance of "good" prostaglandins. These "good" prostaglandins have a positive effect on the immune system, the body's ability to heal itself, the blood clotting factors, and more. His arguments are quite elaborate, and unless you are very familiar with fat metabolism and prostaglandins, a bit tedious. At times he simply dismisses whole bodies of research that do not fit into his model, i.e., all of the research on the beneficial effects of flaxseed oil he dismisses as stating it imitates that action of aspirin, which is just not true.

My biggest criticism involves the lack of published research supporting this diet. What Dr.Sears has basically presented is a hypothesis. It is from this point that you would then begin your research in crnest and perform studies. Over the last year or so, I have been unable to locate any scientific studies published by Barry Sears, Ph.D., related to his diet theory. My main search vehicles have been the online service Medline (available through America Online), and a search service called Focus On through the Institute for Scientific Information. In his book Enter the Zone ,he mentions some pilot studies, but since nothing is foot-noted and no references are given, I assume his data is unpublished; however, I have ordered a list of related studies from his 800 number hotline at the back of the book.Why are published studies important? Publishing your findings in a peer-reviewed journal allows others in your field to examine your research design (number of people in your population, type of people, type of study, methods of evaluation of data), your data, and your conclusions. A responsible journal will not print seriously flawed studies. Once the study is printed, other scientists can run studies using the same criteria and evaluate whether or not they achieve the same results or not your results are reproducible.

So why do we need studies when people like Jenny Thompson have done so well on that diet? Maybe Jenny Thompson would have done equally well at that point in time with the same coaching, the same psychological state of mind, if she had been eating nails. However, if you, or better yet, a scientist tells a person "if you eat XYZ you will perform much better, it should ccome as no surprise that that person will perform much Ii That is Psychology 101 or "the power of suggestion." He mentions other swimmers such as Phil Whitten, Masters swimmer who broke four world records while consuming this diet I have to ask myself, what does Laura Val, who holds numerous records for women 40-44 years old, eat? If I ate what she ate, would I swim as fast?

Another point that really bothers me throughout the book, is his basic assumption that the American people have been religiously following this high carbohydrate diet, exercising a lot, and still find themselves overweight. Most surveys show that most Americans are not eating recommended amounts of fruits and vegetables, often eating too much protein (maybe it would be the right amount to put them in the zone), and way too much fat. Less than half the American population exercises with regularity, and of that a small percentage burns the equivalent of 2000 kcal per week doing vigorous exercise. With the proliferation of fast foods (pizza, french fries,...) processed foods, overeating, combined with the lack of exercise, I don't think it is that mysterious why large parts of the population are too fat.

Most sensible, balanced diets have as their keyelement portion control. The zone diet is no different. Neither is Weight Watcher's diet. Neither are any number of recommended diets. I think that the only true way to evaluate how well this system works is to see if people are able to stay on this dietfor three or more years, and how healthy they are.

Jessica Seaton, D.C. is a chiropractic orthopedist who has been in private practice in West Los Angeles for the past ten years. She now swims with West Hollywood Aquatics. Feel free to e-mail here at Jseaton@aol.com or to call her with any questions at (310) 470-0282.