Dr. Barry Sears, who developed the Zone diet, claims it is closely linked to ideas of human evolution, with the aim of preventing "diet-controlled inflammation." The benefits include healthier weight, less sickness, and slower aging.
Just 8,000 years ago, grains, bread, and pasta were not part of the human diet. Human genes change as their environment changes, but this is a slow process.
Therefore, even 100,000 years is a relatively short period in evolutionary terms. The Zone diet takes this into account and provides a diet plan based on what foods we should eat, according to our genetic makeup.
- Meal plans make use of lean meats and natural carbohydrates.
- Reducing inflammation is the primary goal.
- Critics of the diet point out that fewer carbohydrates can lead to a lower fiber intake.
- Maintaining insulin levels within what Dr. Sears calls a "therapeutic zone," makes it easier to burn excess body fat and keep it off permanently.
What is the Zone diet?
The Zone diet was designed to reduce so-called dietary inflammation. The development of many conditions and diseases involves inflammation. These range in severity from mild gastrointestinal or digestive issues, to playing a role in the onset of cancers and other serious illnesses.
The Zone diet involves some basic rules:
- A meal or snack should be eaten no later than 1 hour after waking up in the morning.
- The interval between meals should be 4-6 hours.
- A meal should be eaten between 2-2.5 hours after a snack, whether the person is hungry or not.
- The individual should drink eight 8-ounce glasses of water a day.
The meal or snack should start with a low-fat protein. Then the person can add good carbohydrates with a low glycemic index, such as vegetables and fruits, and good fats, such as olive oil or avocado.
Typical meal protein should be about 4 ounces for men and 3 ounces for women.
Before every meal or snack, a person should assess their hunger level. If they are not hungry and their mind is clear, they are in "The Zone."
Guidelines include eating three meals and two snacks every day. Each meal must have some protein, about the size of a small chicken breast, and each snack should contain some protein.
The more carbohydrates people consume, the more insulin they secrete. Insulin turns excess carbohydrates into stored fat. Dietary fat does not trigger insulin secretion.
As a result, Zone diet meal plans focus on eating:
- low-density carbohydrates
- dietary fat
The Zone diet has four "pillars," or aims that a person has to bring together to make it part of their way of life. They are to:
- restrict calories without hunger or fatigue
- maintain appropriate levels of inflammation in the body
- use dietary polyphenols to activate genes for improved wellness
- control the inflammation caused by gut microbes
People who follow the diet should balance carbohydrates, fats, and proteins in the following proportions:
- 40 percent carbohydrate
- 30 percent fat
- 30 percent protein
The idea is that by roughly balancing these three things in each meal, a person's health and weight will improve.
In the Zone diet, calorie intake does not have to go down, but what the person is eating has to change.
According to Sears, the benefits of achieving "the Zone," aside from weight loss, are improved mental focus, and increased energy and vitality.
Why does dietary inflammation occur?
For the last few hundreds of thousands of years, people have mostly eaten food from two food groups:
- lean protein
- natural carbohydrates, such as fruits and fiber-rich vegetables
Sears argues that human genes are still those of the hunter-gatherer, rather than the farmer. Farming is a relatively new phenomenon, as far as our genes are concerned. In other words, our genes have not yet adapted to a diet of consuming farmed products.
People are not programmed to consume large amounts of processed carbohydrates. When they do, unpleasant biochemical reactions occur within the body.
Why is it called the Zone diet?
Keeping insulin levels within the therapeutic zone means staying in "The Zone." Zone diet foods need to be taken in the right proportions to help to control insulin production.
What are the consequences of excess processed carbohydrates?
According to the Zone diet theory, the consequences of eating a high proportion of processed carbohydrates include:
According to Sears, the Zone Diet provides the fuel the body needs for optimum health.
Potatoes and whole grains are important sources of fiber, as well as of carbohydrates. Fiber in these foods, and many others, feed healthy gut bacteria and promote long-term health.
A vegetarian diet would be very difficult to follow using the Zone diet's guidelines. However, Sears does not comment on the many studies that show vegetarian and plant-based diets, which are higher in carbohydrate and lower in protein than the Zone diet, also result in significantly lower chronic disease and obesity.
The Zone diet's recommendation to avoid certain fruits and vegetables has been questioned. Most fruits and vegetables are thought to play a valuable role in a balanced diet. The American Heart Association urges people to eat a variety of fruits and vegetables and to include, for example, bananas and raisins with breakfast.
Diabetes U.K. lists as a "myth," the idea that certain fruits are bad, noting that "grapes and bananas, like all fruit, make a very healthy choice."