"There are now about 100,000 different types of protein-producing plants that are almost completely ignored as food staples. These unused protein suppliers are the fungi, which include the yeasts, mushrooms and molds. ...there are many carbohydrate-containing plants that can be used as food for fungus... in low-protein areas of the world. ...even wood pulp has been a fair starting material for the protein-manufacturing machinery of the '. Dr. [William D.] Gray has calculated that if only seven major crops were converted into fungal protein, the protein would meet the yearly needs of more than four and a half billion people."