The Zone Diet
The Zone diet is a diet popularized in books by Barry Sears. It advocates balancing protein and carbohydrate ratios instead of caloric thinking as an approach to eating. It is not primarily a weight-loss "diet" (though it can be used quite successfully for that purpose); rather it is a way of eating — the intake of food that produces the best results within the human body based on a hypothesis of how it has evolved to cope with varying food intake through the ages.
"The Zone" is Sears's term for proper hormone balance. When insulin levels are neither too high nor too low, and glucagon levels are not too high, then specific anti-inflammatory chemicals (types of eicosanoids) are released, which have similar effects to aspirin, but without downsides such as gastric bleeding. Sears claims that a 30:40 ratio of protein to carbohydrates triggers this effect, and this is called 'The Zone.' Sears claims that these natural anti-inflammatories are heart and health friendly.
Additionally, the human body in caloric balance is more efficient and does not have to store excess calories as fat The human body cannot store fat and burn fat at the same time, and it takes time (significant time if insulin levels were high because of unbalanced eating) to switch from the former to the latter.[citation needed] Using stored fat for energy causes weight loss. The diet centers on a "40:30:30" ratio of calories obtained daily from carbohydrates, proteins, and fats, respectively. The exact formula is always under debate, but studies over the past several years (including a non-scientific study by Scientific American Frontiers) have shown that it can produce weight loss at reasonable rates.
More About the Zone Diet Program
Hormonal paradoxes
Sears emphasizes a hormonal paradox of which "low-fat" advocates
were unaware, namely that low-fat diets increase the production of
the hormone insulin, causing the body to store more fat. He points
to the cattle ranching practice of fattening livestock efficiently
by feeding them lots of low-fat grain. He and others have noted the
irony that human diets in the West for the last twenty years have
been full of low-fat carbohydrates, yet people are more obese —
Sears claims as a result.
Additionally, Sears describes fat consumption is essential for
"burning" fat. Monounsaturated fats in a meal contribute to a
feeling of fullness and modulates the rate at which carbohydrates
are absorbed into the bloodstream. Slower carbohydrate absorption
means lower insulin levels which means less stored fat and a faster
transition to fat burning. If the body needs energy and can't burn
fat because of high insulin levels, a person feels tired as their
brain starves and metabolism slows to compensate. This occurs
because the the brain runs on glucose and high insulin levels
deplete blood glucose levels. Such condition, rebound hypoglycemia
causes sweet cravings(which just starts the high-insulin cycle all
over again.
The "low-carb craze"
Low-carbohydrate diets like the Atkins diet became extremely popular
throughout the United States in 2003 and 2004, but Sears claims that
they miss the point. According to him, they ignore the importance of
hormonal balance, as well as the influence of dietary balance on
digestion and hormone production. In addition, high-protein/low-carb
diets cause the production of some "bad" hormones that the body
tries to flush from the system. Much of the initial weight-loss from
such diets is water loss.
The Zone in Italy
In Italy the Zone has been "translated" by Gigliola Braga, a
biologist who applied Sears' method to the local food and habits.
Criticism
The American Heart Association does not recommend the Zone Diet due
to high-protein, lack of essential nutrients and little information
on long-term effects.