But humans are perverse, not sensible. Deciding on the basis of artificially-created flavors, preferring incipid textures, we seem to prefer junk food and become slaves to our food addictions. For example, in tropical countries there is a widely grown root crop, called in various places: tapioca, tavioca, manioc, or yuca. This interesting plant produces the greatest tonnage of edible, digestible, pleasant-tasting calories per acre compared to any other food crop I know. Manioc might seem the answer to human starvation because it will grow abundantly on tropical soils so infertile and/or so droughty that no other food crop will succeed there. Manioc will do this because it needs virtually nothing from the soil to construct itself with. And consequently, manioc puts next to nothing nourishing into its edible parts. The bland-tasting root is virtually pure starch, a simple carbohydrate not much different than pure corn starch. Plants construct starches from carbon dioxide gas obtained the air and hydrogen obtained from water. There is no shortage ever of carbon from CO2 in the air and rarely a shortage of hydrogen from water. When the highly digestible starch in manioc is chewed, digestive enzymes readily convert it into sugar. Nutritionally there is virtually no difference between eating manioc and eating white sugar. Both are entirely empty calories. If you made a scale from ideal to worst regarding the ratio of nutrition to calories, white sugar, manioc and most fats are at the extreme undesirable end. Frankly I don't know which single food might lie at the extreme positive end of the scale. Close to perfect might be certain leafy green vegetables that can be eaten raw. When they are grown on extremely fertile soil, some greens develop 20 or more percent completely digestible balanced protein with ideal ratios of all the essential amino acids, lots of vitamins, tons of minerals, all sorts of enzymes and other nutritional elements--and very few calories. You could continually fill your stomach to bursting with raw leafy greens and still have a hard time sustaining your body weight if that was all you ate. Maybe Popeye the Sailorman was right about eating spinach. For the moment, lets ignore individual genetic inabilities to digest specific foods and also ignore the effects stress and enervation can have on our ability to extract nutrition out of the food we are eating. Without those factors to consider, it is correct to say that, to the extent one's diet contains the maximum potential amount of nutrition relative to the number of calories you are eating, to that extent a person will be healthy. To the extent the diet is degraded from that ideal, to that extent, disease will develop. Think about it! Lessons From Nutritional Anthropology