There is a lot of confusion about "superior" and "inferior" proteins—so called "complete" and "incomplete" foods. At the beginning of the century, researchers doing animal experiments discovered that rats could live and grow on a single food such as eggs. Eggs, like meat, fish, and cheese, were therefore dubbed "complete" proteins. Vegetable foods such as rice, legumes, seeds, nuts, corn, and wheat were called "incomplete" since on their own they were unable to maintain life and growth. What all this meant is that the so-called "complete" proteins contain all the eight acids which humans cannot make for themselves in adequate amounts. But what they didn't take into account is that vegetable food—say, corn— together with another—say, red beans—also contains the eight essential amino acids and, provided you eat one vegetable together with another, you are getting the full complement of the eight essential amino acids in good balance. Better still, you are getting them without the fat that accompanies protein from animal foods. The idea that we need animal foods in order to be healthy is simply untrue. Populations numbering in the millions in different parts of the world have lived and developed enviable health and strength for thousands of years on a purely vegetable diet.
The best—and often the cheapest—sources of protein are the unrefined, unprocessed vegetable foods—complex carbohydrates complete with their natural fiber content, vitamins, and minerals—whole grains such as rice, wheat, oats, barley, legumes including lentils and beans; mixed seeds or mixed nuts; fruits, and vegetables from salad greens to carrots and potatoes. Eaten together in salads and casseroles, bread and soups, they provide low calorie menus without the danger of high fat from the intake of animal foods. The Lifestyle Diet provides 15 percent of your daily calories in the form of protein. It allows you to eat four ounces of meat, fish, or poultry (preferably fish) three times a week. On the days when you choose not to eat these foods you can have instead four ounces of mixed nuts or two eggs. It completely eliminates all cheese except those such as cottage cheese and curd cheeses made from low-fat milk.
If you prefer, you can take all your protein from vegetarian foods. The question of a vitamin B12 deficiency on a vegetarian diet is always brought up as evidence of the need to eat meat, although long ago biochemist Schweigert of the American Meat Institute researched the question and discovered that the need for B12 rises and falls with the amount of protein eaten. B12 is available in dairy products and eggs included in the Lifestyle Diet. In this kind of protein-economical diet it is correspondingly low. Schweigert also discovered that the whole wheat grain is a usable source of B12 provided it is not processed into white flour. If it had not been, then the millions of people in different countries who have lived almost exclusively on a vegan diet (vegetarian with no milk, dairy products, or eggs) would have suffered B12 deficiencies.