An overview of the Zone Diet

Dr Barry Sears, a biochemist, first popularized the Zone diet in his 1995 book, “The Zone”. While this diet has not been developed specifically for weight loss, it is probably more well-known for its weight loss benefits than for any of the other advantages it promises, all thanks to solid media exposure. The popularity of this diet reached its peak in the late 1990s, slipped a bit, and then made a comeback recently following the endorsements of Hollywood A-listers and models such as Jennifer Aniston, Sarah Jessica Parker, Sandra Bullock and Cindy Crawford.

The Zone diet is often classified as a low-carb diet, but Dr Sears describes it as a moderate carb, moderate fat, and moderate protein diet, and regards it as superior to low-carb diets due to the improved hormonal responses. He goes on to say that the Zone diet can not be regarded as a protein rich diet since you never consume more low-fat protein during any meal than you can fit on the palm of your hand.

Many scientific studies are finding that weight management is a lot more complex than simply balancing calorie intake and calorie usage. The Zone approach suggests that inflammation precedes obesity. If that is true, any obesity problem can only be addressed by resolving the underlying inflammation.

Dr Sears also believes that inflammation is the underlying cause of many other chronic diseases, and that our diets can either reduce inflammation or increase it. Your ability to control inflammation through your diet becomes the new physical definition of wellness. Some of the chronic diseases resulting from what Dr Sears calls “Silent Inflammation” include general fatigue, headaches, insulin resistance, obesity, diabetes II, ADHD and even cancer.


How does it work? According to Dr Sears, the human body can manufacture anti-inflammatories from our diet. The Zone Diet is described to be an “anti-inflammatory” diet since it was designed to up-regulate the production of powerful anti-inflammatory eicosanoids while simultaneously down-regulating the production of pro-inflammatory eicosanids that cause pain. As per Wikipedia, “eicosanoids” are signaling molecules derived from omega-3 or omega-6 fats. They exert complex control over many bodily systems, mainly in inflammation or immunity, and act as messengers in the central nervous system.

The anti-inflammatory response of the Zone Diet therefore comes from its ability to manipulate the levels of eicosanoids by controlling the protein to carbohydrate ratio as well as the ratio of omega-6 to omega-3 fatty acids. The “Zone” refers to a state in the human body where its hormones are in balance and where inflammation is reversed. The main hormones to be influenced directly by the diet are glucagon and insulin. By eating correctly, according to this approach, the body automatically fixes the balance between these two hormones.

Similar to Atkins, Sears emphasizes that low-fat diets increase the production of the hormone insulin, causing the body to store more fat. He used the cattle ranch practice of fattening up livestock by feeding them plenty low-fat grains as an example. Sears also expressed the same belief Atkins did with regards to the low-fat diet; namely, that the low-fat dogma itself is probably to a large degree responsible for the obesity problem in the United States. Both of them stressed the fact that fat consumption (the right fats of course) is absolutely essential for “burning” fat.

Despite claims made in the book, there is little research to support Dr Sears’ claims for his anti-inflammatory diet. On March 7, 2007 a study was published in JAMA (The Journal of the American Medical Association) comparing the Zone diet to other popular diets. The nutritional programs selected were: Atkins (very low in carbohydrate), Zone, LEARN (Lifestyle, Exercise, Attitudes, Relationships, and Nutrition; low in fat, high in carbohydrate, based on USA national guidelines), and Ornish (very high in carbohydrate). This study was aimed at pre-menopausal women and took place over a period of 12 months. Women on the Atkins Diet lost an average of 4.7kg, while the averages for the other diets were: Zone – 1.6kg, LEARN – 2.6kg, and Ornish – 2.2kg. It went on to find that after 12 months, the secondary outcomes (health factors) all groups were very similar.

A non-scientific study by the PBS documentary “Scientific American Frontiers” has shown that the Zone diet can produce weight loss at reasonable rates. The team performing the study was surprised by the outcome of the study, which compared the effectiveness of several popular diets including the Zone, Weight Watchers, Gastric Bypass Surgery, and the Mediterranean Diet. The participants on the Zone experienced the greatest fat loss while simultaneously gaining muscle mass.

Despite the lack of scientific evidence the internet abounds with testimonials from satisfied Zone customers. In the USA, there are plentiful evidence that the Zone is more than just a brief fad. Many companies sell Zone dietary plans and bars via 1 800 numbers and internet websites, and there are whole ranges of food products (e.g. pancake mix) all proposing to be “Zone favorable”. In addition to this, many restaurants and fast food places proudly offer menus and meals also carrying this tag. This suggests that the Zone diet is around to stay and has developed the necessary market clout to remain a force to be reckoned with.

This calorie restricted diet allows for the consumption of carbohydrates, protein and fats in a strictly enforced ratio of 40:30:30 for all meals and snacks to accomplish this goal. Followers of this dietary approach must eat a meal or a snack (designed to comply with the ratio above) every 5 hours. To make the program easier for dieters to adhere to Dr Sears has organized food into “carbohydrate blocks”, “protein blocks” and “fat blocks” and has set up formulas of how many blocks should be eaten at each meal and snack. In his latest books “Zone friendly” recipes are also provided. Dr Sears and other companies provide additional help for the followers, these come in the form of personalized dietary plans and menus, and special bars with a 40:30:30 composition.

To get started on the Zone, Dr Sears recommends reading his paperback book, “A Week in the Zone”. This is basically the Zone for Dummies. It is a quick read that gives you all the necessary information to start the program.

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