[4][7] It begins with the determination of the individual's protein requirement for daily replacement due to various loss mechanisms.
The Zone diet proposes that a relatively narrow distribution in the ratio of proteins to carbohydrates, centered at 0.75, is essential to "balance the insulin to glucagon ratio, which purportedly affects eicosanoid metabolism and ultimately produces a cascade of biological events leading to a reduction in chronic disease risk, enhanced immunity, maximal physical and mental performance, increased longevity and permanent weight loss.
"[1] The diet advocates eating five times a day, with 3 meals and 2 snacks, and includes eating proteins, carbohydrates – those with a lower glycemic index are considered more favorable, and fats (monounsaturated fats are considered healthier) in a caloric ratio of 30%-40%-30% (fat-carb-pro).
There is a more complex scheme of "Zone blocks" and "mini-blocks" that followers of the diet can use to determine the ratios of macronutrients consumed.
When properly evaluated, the ideas and arguments of popular low carbohydrate diet books like the Zone rely on poorly controlled, non-peer-reviewed studies, anecdotes and non-science rhetoric.