“One will starve to death with just as much certainty and much more speedily, if one attempts to live upon foods containing only one or two elements of nutrition, as if one were totally abstaining from food. A diet of white flour and water, or white sugar and water, will result in death much sooner than a diet of water only. If no food is eaten the body feeds upon its own food reserves, but it has no provision for meeting the exigencies created by prolonged subsistence on one-sided diets.”