Active persons are going to reap the most benefit if their allotment of carbs, protein, and fat ranges between the 40-30-30 ratio prescribed by the Zone diet and the 65-15-20 supported by many sports nutritionists.
THE USDA, THE FEDERAL AGENCY that develops guidelines on how to eat, has relied on its ubiquitous Food Guide Pyramid to spread nutrition information to the public for more than a decade. Since its inception, however, many nutrition experts have questioned how well the tool has worked. "The pyramid needs a drastic revision," says Michael Jacobson, executive director of the Center for Science in the Public Interest.
Why? Many feel that the food pyramid isn't dramatically flawed; it's just dangerously vague. It places foods into rigid categories, with "bread, cereals, rice, and pasta" at the bottom, fruits and vegetables on the next tier, meat and dairy on the next, and sweets at the top. The pyramid tells you how many servings of each group you should be getting daily, but not the size of those servings. As a result, some of us have been eating way too much. Even more problematic is the overwhelming array of products that seem to fall loosely into the pyramid categories. We're encouraged to make breads, cereals, rice, and pastas the foundation of our diet, but such thin information hardly helps us make an informed decision in the store. These issues might be addressed when the pyramid gets overhauled in early 2005. In the meantime, allow us to help you out.
We'll spare you a graduate seminar in nutrition, but you won't get very far on your food journey without knowing a few basics about macronutrients—that is, carbohydrates, fat, and protein. First and foremost, you need all three, every day, in appropriate proportions. The trouble comes in differentiating good carbs, fats, and protein from bad. Organic spelt bread, for example, is a carbohydrate. But so is Cap'n Crunch. Most ice cream is high in fat; so is olive oil. Salmon has protein; so does a Big Mac. And these are the easiest to distinguish. It's not the macronutrients that are the problem; it's our understanding and use of them.
The optimal ratio of macronutrients is unique for each individual, but here are some road rules to steer you back into balance. The body uses carbohydrates as its primary fuel source, meaning it burns carbs before it burns fat or protein. The more active you are, the more carbohydrates you need. The higher the quality of those carbs—think carrot sticks or cantaloupe—the more you'll benefit from them in terms of vitamin richness and long-lasting energy.
The problem is, many carbs are processed to the point where much of their nutritional benefit has been vaporized, as in many popular breakfast cereals. Overprocessed carbs are stripped of fibrous hulls, ground into microfine particles, then packed with sugar, salt, and hydrogenated fat for taste, and preservatives for shelf life. These carbs break down quickly in the bloodstream, causing a spike in insulin—an effect known as the glycemic response—which turns carbs into fat in greater proportions and also leaves you hungrier sooner. The glycemic response caused by a given food is measured by its glycemic index. You can find an extensive listing of foods at www.glycemicindex.com to help you distinguish between good and bad starches and take better dietary control of blood-sugar fluctuations. Get to know the list; it's a key part of eating better.
As for protein and fat, we need those in smaller quantities, though they are still essential for our health and fitness. The best benefits are delivered if your total-calorie intake shakes out somewhere between the 40-30-30 carb-protein-fat ratio advocated by Dr. Barry Sears in his Zone diet and the roughly 65-15-20 carb-protein-fat allocation supported by many nutritionists. The specific numbers, however, are less important than eating mostly good carbs, with some protein and fats to round out the calories.
Your homework assignment, then, is to familiarize yourself with both the glycemic index and the wide variety of foods—both good and bad—that fall into the carbohydrate, protein, and fat categories. (For a few examples, see "Mean Cuisine,") Once you can look at a plate—or a day—of food and identify the relevant macronutrient ratios, you're on your way to optimal health.