Sometimes in emphasizing the fact that vitamins, minerals, and specific amino acids are indispensable for normal nutrition, the fundamental necessity of the body for energy is overlooked. The calory has become widely known and used in this country and abroad as a unit for measurement of heat. Either directly or indirectly the heat of the body is derived from the food ingested. In their article "Energy Metabolism" (Ann. Rev. Physiol.5:105, 1943), Dr. E. B. Forbes and Dr. LeRoy Voris stated, "In the sense that the most conspicuous attribute of life is motion, that motion is an expression of energy, and that all nutrients essential to the life of animals, including man, are involved directly or indirectly in energy production, energy metabolism affords a significant point of view—a common denominator—in terms of which all nutrients may be studied and compared."
It is indeed difficult, if not impossible, for the