Whereas these diets allow virtually unlimited consumption of fish, poultry, meat, eggs, bacon, sausage, butter, cream, etc., the Zone protocol prescribes a protein limit and allows far smaller portions of these foods. The Zone prescription for complete protein is not much higher than the RDA for protein. In contrast, Zone guidelines require that carbohydrates from non-starchy vegetables and fresh fruits provide most of the calories, and they allow for very modest portions of starchy vegetables, grains, dried fruits, and even sweeteners. This is three to four times the amount of health protective vegetables and fruits recommended by the National Cancer Institute and USDA's Food Guide Pyramid. Some anti-fat fanatics have been advocating diets that provide much less than 30 percent of calories as fat.
Snacks are to contain even less.
Most doctors, nutritionists, and dieticians accept the commonly held notion that weight loss can only be achieved on a reduced calorie diet. The Zone diet, as outlined by Dr. Sears, will provide between 800 and 1200 calories per day for most people, so it is definitely a low calorie diet. Further, research over the past 25 years has consistently shown that low calorie diets composed primarily of carbohydrates will actually promote fat gain while a high calorie, high protein, high fat, low carb diet will promote fat loss. The truth is that most criticisms of the Zone diet miss the mark, and in general, the Zone recommendations are a tremendous improvement over the high carb, low protein, and low fat diets which have swept the nation. However, as it is currently outlined, the Zone diet is too low in calories to be healthful.