Life is a constant battle against entropy. All living things are well-ordered structures with low entropy (degree of disorder) and the second law of thermodynamics demands that entropy levels are always trying to increase. Animals fight this tendency by eating low entropy plants (or other animals), breaking them down to release entropy, thus satisfying the second law, and retaining low entropy components, i.e. highly-ordered and high energy molecules such as glucose. If we stop eating, our bodies start to disintegrate and we die – entropy wins as the molecules of bodies are dispersed.
Plants use sunlight to fight the entropic battle. In photosynthesis, low entropy solar energy converts carbon dioxide and water to oxygen and glucose with the creation of entropy in the form of dispersed heat.
It has been reported recently that there are more people suffering from obesity in the world than from malnutrition (http://www.ifrc.org/en/publications-and-reports/world-disasters-report/wdr2011/). This might suggest that global society has a major distribution problem to solve and that current approaches are failing. This is a tentative conclusion supported by another recent report which estimates that half of global food production is wasted (http://www.imeche.org/knowledge/themes/environment/global-food). Some agricultural production never reaches the distribution system and rots in the fields, while some is disposed of untouched by end-purchasers. Presumably end-purchasers throwing away uneaten food are not starving and probably a high proportion of them are obese.
The second law of thermodynamics demands that there must be waste in all processes, so we can never reduce the wasted food production to zero but 50% wastage seems high and perhaps implies we some way to go before population growth is limited by food production (see post on ‘Two Earths’ in August 13th, 2012 or ‘Population crunch’ on September 15th, 2012). Of course, if the majority of current food production is unsustainable then we are in trouble already.