The Zone Diet
The Zone diet, invented by biochemist Barry Sears, prescribes consuming calories from carbohydrates, protein, and fat in a balanced ratio. This ratio, 40% carbs, 30% protein, and 30% fat, is said to be optimal for human efficiency.
While some nutritional experts have criticized the Sears's claims in substantiating the Zone diet, studies have generally shown it to be effective. Additionally, it may be easier to follow than other, more restrictive diets such as Atkins or the Paleo Diet.
Many products labeled "Zone" exist in markets worldwide, but of course the 40:30:30 balance can be achieved through an unlimited combination of foods, whether you're cooking at home, ordering at a restaurant, or serving yourself in a dining hall setting. The following diagram provides one easy rule-of-thumb to follow when filling your plate:
The Paleo Diet
The Paleo Diet, as mentioned above, is a restrictive diet. It is based on the premise that genetically, we are scarcely different than our prehistoric ancestors of 10,000 years ago, prior to the agricultural revolution. As such, our digestive systems are evolutionarily adapted to eat as they did. This means eating mainly meats, fish, fruits, vegetables, roots and nuts, and excluding dairy, grains, legumes, salt, refined sugars, and processed oils.
Proponents of the Paleo diet argue that modern populations subsisting on an ancient diet free of modern ingredients and processing are largely free of "the diseases of civilization." These include diabetes, some cancers, heart disease, allergies, and depression.
The Paleo diet's claims are developed, yet controversial. In practice it requires eating radically different than most Americans are accustomed to. If you are considering following the Paleo diet, there is much research out there supporting as well as discrediting the diet's scientific foundations. The following film explains the diet and how it is put into practice: