Until recently, even many scientists were accustomed to classify meats as “first-class” proteins and vegetables as “second-class” proteins, thereby implying that nonanimal sources of protein were somehow inferior in quality. The most current medical and scientific evidence, however, points to other considerations:
• Man can subsist perfectly well on a proper nonflesh diet; • Statistically, vegetarians in the United States are thinner, healthier, and may live longer than meat eaters;
• Meat, especially in the large quantities Americans are accustomed to eating, may be harmful to the body;
• Protein from nonflesh foods can be an adequate nutritional substitute for meat protein. CD-SG 37.1
Protein is essential to life: It is the substance that the body uses to build and replenish its organs, skin, cartilage, nails, hair, muscles, and the organic framework of bones. The proteins that our bodies use are composed of 22 amino acids, not all of which must come from the diet. The human metabolic system can synthesize (produce by uniting chemical elements) 14 of these 22 amino acids, but the remaining 8 must be obtained from food sources outside the body. Hence their name—the essential amino acids. CD-SG 37.2