The Zone Diet

The Zone diet is a diet popularized in books by Barry Sears, which advocates "hormonal thinking" in approach to weight loss, rather than caloric thinking.

The term, "the Zone," is Sears' term to describe proper hormone balance — insulin levels in the body being neither too high nor too low — as vital to using stored bodyfat for energy, causing one to lose excess weight. The diet centers around a "40:30:30" ratio of carbohydrates, proteins, and fats, respectively. The formula is considered controversial, but studies over the past several years (including non-scientific study by Scientific American Frontiers) has shown to achieve weight loss quickly.

Hormonal paradoxes

Research, Sears explains, points to an important hormonal paradox which "low-fat" advocates were unaware of, namely that low-fat carbohydrates increase the production of the hormone insulin, causing the body to store more fat. He points to a known fact about cattle ranching: that the best way to fatten cattle is to feed them lots of low-fat grain. Sears and others have pointed out the irony that human diets for the last twenty years have been full of low-fat carbohydrates—and people are more obese, they claim, as a result.

In addition to this, fat consumption is essential for burning fat. Healthy (monounsaturated) fats cause the production of important "command hormone" glucogen which direct other hormones in their use of stored fat in the body. Low-fat diets actually stimulate fat storage, according to Sears, because fat-storing insulin levels are allowed to run out of control.

The "low-carb craze"

The low-carbohydrate diet is fast becoming popular, with the Atkins diet and others, but Sears claims that these miss the point — that they ignore the importance of maintaining a hormonal balance, and how the balance between carbs, proteins, and fat influences the interconnected mechanisms hormones production and digestion.

Advocates of the Zone Diet

Advocates for the Zone Diet include celebrities and also some health experts who say that the Zone’s recommendations don’t stray far from the USDA’s (United States Dietary Association) dietary guidelines. Critics have argued that the Zone Diet has flawed ratios but Sears argues that the Zone diet is really a low glycemic-load diet that has adequate protein. Sears also defends the criticism that Zone Diet is too complicated. He believes this is a misconception because his first book on the Zone Diet was targeted to cardiologists who were more scientifically-oriented.

Critics of the Zone Diet

The AHA (American Heart Association) classifies the Zone Diet as high protein and does not recommend the Zone Diet for weight loss. They assert that the Zone Diet has not been proven effective in the long term for weight loss. They issued an official recommendation warning against diets like the Zone Diet. They believe that the Zone Diet is hazardous as it restricts the intake of essential vitamins and minerals present in certain foods. They are concerned that the protein ratio in the Zone diet is too high even if the minimal fat ratio is good. Robert H. Ecker M.D of the A.H.A., finds the Zone Diet’s theory on insulin flawed and argues that there is no scientific proof that the hormone insulin plays a big role in weight regulation.