The Zone Diet remains one of the most misunderstood concepts in nutrition. It is not a weight loss program any more than the Mediterranean diet is a weight loss program. It is a dietary roadmap developed for three distinct purposes: (1) the control of hormonal responses generated by the diet, (2) the reduction of inflammation, and (3) the altering of gene expression, and in particular the silencing of inflammatory genes. The Zone Diet is ultimately based on an understanding of the fundamental nature of inflammatory responses that are deeply embedded in our genes and how the balance of nutrients in the diet can either turn on or turn off those inflammatory responses.

Zone Diet as a Blueprint for Dietary Ingredients
The best way to understand the Zone Diet is that it represents a blueprint for putting together food ingredients to generate the best possible hormonal responses to control inflammation. This is why terminology is so important when trying to describe diets. Often the word “diet” is used incorrectly if it only describes food ingredients without also instructing a person how to balance those same food ingredients. Examples of this would include the Paleolithic diet or the Mediterranean diet. Each only describes the types of ingredients that might be used, but neither one provides any detail about the actual balance of ingredients that will result in the optimal hormonal balance.

For example, a Paleolithic diet simply means using ingredients available in Paleolithic times. This means fish, beef, and eggs as protein sources, fruits and vegetables as carbohydrate sources, and nuts as a fat source. These represent a rather restrictive group of food ingredients, even though they have the least inflammatory impact on our bodies compared to more recent food ingredients, such as grains, legumes, dairy, alcohol, refined carbohydrates, and refined vegetable oils. But how to balance those ingredients to achieve the best hormonal response is never addressed in popular books on this subject. It is somehow left to intuition. That’s a very tricky proposition. For example, do you balance those Paleolithic ingredients in such way to generate a PaleoAtkins diet — rich in protein and fat but very low in carbohydrates? Or how about a PaleoOrnish diet rich in fruits and vegetables, but very low in protein and fat? However, if you follow the Zone Diet blueprint, you end up with the PaleoZone diet with a balance of protein, carbohydrate, and fat. Each of these diets will generate vastly different hormonal responses even though you are “eating clean” using Paleolithic food ingredients.

Not having a dietary blueprint for meal construction is similar to building a house without a blueprint after the lumber and bricks have been delivered to the construction site. You will probably get some type of shelter, but it would have been a lot better house if you had used a blueprint from the beginning.

Virtually all the popular books describing Paleolithic diets never give any blueprints for balancing of Paleolithic ingredients. They assume your body will somehow “know”. Fortunately, the top academic researchers in Paleolithic nutrition finally put together a “blueprint” for their best estimate of the macronutrient balance for the Paleolithic diet, which was published in a 2010 article in the British Journal of Nutrition. Their estimates were that the Paleolithic diet consisted of 40% of the calories as carbohydrates, 30% as protein, and 30% as fat. That’s virtually identical to the dietary blueprint that I described in The Zone 15 years earlier. Furthermore, they estimated that the Paleolithic diet should contain about 6 grams of omega-3 fatty acids per day just as I had recommended in The OmegaRx Zone eight years earlier.

Maybe I made a couple of lucky guesses years earlier, or just maybe the existing science at the time I made my dietary recommendations was compelling enough for me to take a strong position where others were strangely silent.

Mechanics of the Zone Diet
Trying to construct meals on dietary percentages is useless because of the perceived complexity. Actually all you need is one hand and one eye. You can approximate a 40/30/30 balance simply by dividing the plate at every meal into three equal sections. On one-third of the plate you put some low-fat Paleolithic source of protein (egg whites, fish, chicken, etc.) that is no larger or thicker than the palm of your hand. This amount of protein is about 4 ounces and contains about 30 grams of high-quality protein. You fill the other two-thirds of the plate with Paleolithic carbohydrates (primarily vegetables and limited fruits). You could finish it with some Paleolithic fat (nuts) or go Mediterranean and add a dash of olive oil. This very simple method will provide pretty close to a 40/30/30 balance of calories every time. What’s your indicator that such a macronutrient balance is generating the correct hormonal response? It is your lack of hunger for the next four to five hours. This lack of hunger means that you have stabilized blood sugar levels with the right balance of protein and carbohydrate.

Seems simple enough, and it is. The only hard part is the doing the best you can every meal for the rest of your life, assuming you believe that hormonal control is important. Studies from Harvard Medical School in 1999 indicated that even the best hormonal balance from a meal could only be maintained for about five hours. This means you should be eating this Zone macronutrient balance every five hours to maintain the hormonal benefits throughout the day. Functionally this means eating three meals and two snacks every day, making sure that there is never more than five hours between a Zone meal and/or a Zone snack. This is easier than it initially seems. Simply eat your first Zone meal within an hour of waking. If that is 7 a.m., you should eat a Zone lunch no later than noon. Most people have dinner later than 5 p.m., meaning the late afternoon is ideal for a small, balanced Zone snack because most people eat dinner at 7 or 8p.m. Of course, that should also be a Zone dinner. Finally before you go to bed, eat another small balanced Zone snack to keep the brain fueled throughout the night.

Role of fish oil to reduce inflammation
The Zone Diet is designed to reduce inflammation, which can be further enhanced by supplying adequate levels of high-purity fish oil rich in the omega-3 fatty acids EPA and DHA. The amount I recommend to the average person is about 2.5 grams per day increasing to 5 grams per day for active individuals and still increasing more to 7.5 grams per day for elite athletes. The more intense the exercise, the more that inflammation in the body is induced by that exercise.