The Zone Diet was created by biochemist Barry Sears and popularized in several books. This particular diet is in favor of balancing your proteins and carbohydrates in a 30:40 ratio. It is not primarily considered to be a "weight loss" diet, although it is frequently used as one for weight loss and with success.
The Zone Diet centers at 40:30:30 ratio of calories that are obtained from a balance of carbohydrates, proteins and fats, respectively. The exact formula has been under debate for several years, but the majority of studies have shown that this particular formula can result in weight loss and at a reasonable rate.
The Zone is considered to be one of the easiest diets to conform to because you don't suffer from hunger or fatigue, but you are able to lose weight at the same time. Those people who do experience fatigue have noticed it disappears with two or three days after beginning the plan.
"The Zone" is what Sears uses as a term for proper hormone balance. If your insulin levels, glucagon levels are neither too high nor too low, then the body produces what is called "anti-inflammatory chemicals." These have the same effect as aspirin does. The ratio of 30:40 for proteins and carbs is said to trigger this effect and thus you are in "the zone."
At the same time, the diet claims that the human body's caloric balance is also more efficient when in "the zone," as the body does not need to store the excess calories as fat. Sears believes that the body cannot store and burn fat at the same time and that it takes time for the body to switch gears into burning fat mode, which is key to weight loss. Another important aspect of this diet is that you should take Omega-3 and Omega-6 fatty acids.
Sears considers fats to be an important part of actually "burning" fat as well. He believes that monounsaturated fats in your meals help to give you a feeling of fullness. At the same time, they also help to slow the rate at which carbohydrates are absorbed by the bloodstream. If you slow down the rate that carbohydrates are absorbed, then you lower your insulin levels and less fat is stored. This helps the body to transition to fat burning much more quickly.
The typical Zone meal is as follows. Eat as much protein as the palm of your hand. Eat as many non-starchy raw vegetable as possible and enough carbohydrates to maintain mental clarity. The carbohydrates are important because the brain runs on glucose.
The Zone diet is considered to be a low carb diet, but it is not as restrictive as diets such as the Atkins diet. Sears believes that carbs are important for hormonal balance as well as digestion and hormone production. He also believes that vegetarian and vegan diets are the extreme when compared to The Zone because you are not consuming protein relative to your carb and vegetable intake.