Although high carbohydrate, low-protein and low-fat diets, meals, and snacks are very popular these days, they may be giving you more than you bargained for. The biochemical and hormonal changes that result from such a diet can lead to chronic fatigue, starch and sweets cravings, mood swings, depression, obesity, PMS, high blood pressure, stroke, cancer, arthritis, autoimmune and immune deficiency diseases, behavioral disorders, and many more ailments.
This is the message of the bestselling book Enter The Zone!, and its sequel, Mastering The Zone, both by biochemist Barry Sears, Ph.D. According to Sears, high carbohydrate diets increase blood levels of insulin, and high insulin levels initiate a chain of biochemical events that make people sick, fat, and fatigued.
Sears advocates eating regularly scheduled, small meals and snacks that each provide 30 percent of calories from complete protein, 30 percent from fat, and 40 percent from carbohydrate, because this macro nutrient ratio keeps insulin levels in the ideal zone — not too high, not too low. When insulin is in this zone you can convert your body fat to energy, reduce cravings, moderate your moods, and increase your energy, endurance, lean body mass, mental clarity and resistance to stress and degenerative disease!
These claims may seem farfetched to those unaware of the profound effect of food and the proportion of macronutrients on human growth, development, and physical and mental health. Food is so basic that many take it for granted. In fact, many have criticized the Zone approach, claiming that the diet is (a) a fad; (b) imbalanced; (c) too high in protein; (d) too low in carbohydrate; (e) too high in fat; or (f) just another impossible low-calorie diet.
Is it a fad diet?
Humans have been on earth at least two million years; for the first 1.99 million years, human diets all over the globe were composed of milk (human), insects, organ meats, meat, poultry, fish, eggs, green and root vegetables, seeds and nuts, and occasional sour fruits. Milk was probably also taken from captured animals. Concentrated, high glycemic carbohydrates such as sugar, bread, pasta, rice, and bagels were not part of early human diets. By studying the few remaining pre-agricultural societies that still survive, anthropologists have shown that the diet that molded human biochemistry and physiology was roughly isocaloric — equal parts protein, carbohydrate, and fat.
Studies by Weston Price, D.D.S. and other anthropologists have clearly shown that populations living on diets free of concentrated carbohydrates have excellent health and long lives. They have virtually no tooth decay, no crooked or impacted teeth, and no obesity, heart disease, cancer, diabetes, vision problems, mental deficiencies, or emotional disorders. In fact, they have none of the degenerative diseases that afflict modern people. However, when these populations switch to modern high carbohydrate diets, they develop all of the diseases that afflict modern man.
Could a diet that has been practiced for two million years and maintained exceptional human health for that period of time be considered a fad?
Is it an imbalanced diet?
A 40-30-30 diet contains almost equal percentages of calories from each macro nutrient: protein, carbohydrate, and fat. That’s certainly more balanced than the high-carb diet, which derives 60-70 percent of calories from carbohydrate, 10-15 percent from protein, and 10-20 percent from fat (but not quite as balanced as an isocaloric diet).
From a visual perspective a 40-30-30 whole foods meal actually looks a lot like a typical Chinese stir-fry (without the rice!): by volume it is about 70 to 80 percent vegetables, 20 to 30 percent lean protein, with a small amount of high quality fat, oil or nuts. That is a very "square" meal!
Is it a high protein, low-carb diet?
Many have confused the Zone approach with high protein, very low carbohydrate diets such as Atkins, Stillman, and Scarsdale diets. Whereas these diets allow virtually unlimited consumption of fish, poultry, meat, eggs, bacon, sausage, butter, cream, etc., the Zone protocol prescribes a protein limit and allows far smaller portions of these foods. The Zone prescription for complete protein is not much higher than the RDA for protein.
High protein, low carb diets generally limit total carbohydrate intake to 30 to 40 grams per day; this allows only three to four servings of non-starchy vegetables, and eliminates all starchy vegetables, grains, fruits, and sweeteners. In contrast, Zone guidelines require that carbohydrates from non-starchy vegetables and fresh fruits provide most of the calories, and they allow for very modest portions of starchy vegetables, grains, dried fruits, and even sweeteners. Eating in the zone, an adult may consume each day 12-20 USDA servings (or three to four pounds) of vegetables. This is three to four times the amount of health protective vegetables and fruits recommended by the National Cancer Institute and USDA’s Food Guide Pyramid.
Whereas low carbohydrate diets induce ketosis, ketosis is impossible on a Zone diet because the Zone protocol calls for a minimum of 81 grams of carbohydrate per day (an intake of more than 50 grams of carbohydrate per day prevents ketosis).
Is it a high fat diet?
Some anti-fat fanatics have been advocating diets that provide much less than 30 percent of calories as fat. To these people a diet providing 30 percent of calories as fat is "high" in fat. But according to the national academy of Sciences Committee on Dietary Allowances, a 30 percent fat diet is a "low fat" diet. (A high fat diet would provide more than 50 percent of calories as fat.)
According to the Zone protocol, well-balanced meals should contain a small portion of fat, in the form of three to four macadamia nuts, nine to 12 olives, one to one-and-a-third teaspoons of oil, one-and-a-half to two teaspoons of peanut butter or tahini, or three to four tablespoons of walnuts. Snacks are to contain even less. Sound like a rich, greasy spoon diet?
Rather than being too high in fat, the calorie-restricted Zone program is more likely too low in essential fatty acids, and it certainly fails to provide optimum amounts of the whole foods rich in the vital fat soluble nutrients, such as true vitamin A (not the same as beta carotene!) and D, and E, which are necessary for proper growth, development, and metabolism.
Is it just another "impossible" low calorie diet?
Most doctors, nutritionists, and dieticians accept the commonly held notion that weight loss can only be achieved on a reduced calorie diet. The Zone diet, as outlined by Dr. Sears, will provide between 800 and 1200 calories per day for most people, so it is definitely a low calorie diet. So what’s the gripe?
Well, some of the same experts say that people "never" stick to low calorie diets. This seems like a double bind — they tell you that low calorie diets are necessary to lose weight, but that no one can do it.
Here’s where reduced carbohydrate diets come to the rescue — there is ample research indicating that low calorie diets providing more fat and protein relative to carbohydrates are easier to adhere to and more productive than low calorie diets having a high proportion of carbohydrates. Further, research over the past 25 years has consistently shown that low calorie diets composed primarily of carbohydrates will actually promote fat gain while a high calorie, high protein, high fat, low carb diet will promote fat loss.
The truth is that most criticisms of the Zone diet miss the mark, and in general, the Zone recommendations are a tremendous improvement over the high carb, low protein, and low fat diets which have swept the nation. However, as it is currently outlined, the Zone diet is too low in calories to be healthful. It is virtually impossible to meet all needs for micro-nutrient (calcium, iron, zinc, B-vitamins, etc.) on a diet of 1200 calories or less.
Although Sears is on the right track, greater fat loss and other health benefits can be gotten from a higher calorie diet that provides only one quarter to one third (25 to 33 percent) of its calories from carbohydrates, primarily in the form of large servings of nutrient-dense non-starchy vegetables. This would still avoid the pitfalls of the very low carbohydrate diets and be more nutritious, satisfying, and sustainable than the calorie-restricted Zone program.
One additional caveat: Although Dr. Sears says that his diet can be followed by vegetarians and vegans if they rely on egg whites, low fat dairy products, and processed soy foods for protein, a vegetarian Zone diet would certainly be deficient in vitamins A, D, E, B3, B6, and B12, and the minerals iron, zinc, chromium, and selenium, and a vegan Zone diet would in addition be deficient in calcium. Since dairy and soy foods lack many of the nutrients best supplied by egg yolks, full fat dairy products, fish, poultry and/or meat, supplementation would definitely be in order for these two groups.
Rachel Albert-Matesz, B.A., has been a nutrition educator and cooking instructor for 12 years. She has taught more than 500 cooking classes and had more than 140 food and nutrition articles published in national health oriented magazines and newspapers.
Don Matesz is a nutritionist certified by the American Academy of Nutrition. He has 20 years of experience in the fields of nutrition, fitness, and natural health care and is the author of over two dozen articles on nutrition published in popular health-oriented journals.