Vegetarianism has, among some groups, a bad reputation. The fact that I have chosen to not eat meat has meant that I have on many occasions been asked, ‘why?’ Here I will attempt to answer that question with a scientific basis, and hopefully provide a new, ecological perspective for those who are interested.
We are, like all animals, dependent upon the environment in which we live. Energy does not flow efficiently from organism to organism, as explained in what is called the ‘ten percent rule.’ Approximately ten percent of the energy in food that is consumed is transferred to the flesh of the consumer. There can be many herbivores in fertile areas (e.g. bison herds) because of the large amount of edible material, such as grass and foliage, which is available to them. However, in those same areas, there are by necessity less animals that eat the herbivores. For example, imagine 1000 units of energy (created by photosynthesis) in the grass of a given area. If in this hypothetical, ultra-simplified example it takes 1 unit of energy to sustain an animal, then there can only be 100 animals that eat the grass (primary consumers), ten animals that eat the primary consumers (secondary consumers), and one animal that eats the secondary consumer (tertiary consumer). The following figure demonstrates this principle.
In this way, energy availability controls the amount of animals that can survive in an area. If hawks could eat grass (directly, rather than indirectly by eating snakes, which acquired energy from mice, which acquired energy from grass, which acquired energy from the sun), there would be a lot more of them.
Human beings are currently acting like apex predators, based upon our meat consumption, though have, in the context of the above figure, an exceedingly ‘mouse-like’ population, due to the recent exponential growth in human population. This is a recipe for disaster. All humans should realize this because we, like all animals, are vulnerable to massive population declines due to the starvation of many individuals if our resource requirements exceed the resources that are available.
A diet that consists of less meat and more plant products substantially reduces energy consumption. According to the June 2016 USDA Acreage report, over 10 percent of the land area in the continental US is used to produce corn and soybeans. In my home state of Indiana, about 48 percent of the land area is used to produce corn and soybeans, according to estimates that I acquired from the Indiana Soybean Alliance and a USDA report. The vast majority of this corn and soybeans are used to feed livestock, which we then eat. By time that we eat a cheeseburger, 99 percent of the energy that was originally in the plants that were used to feed the animal from which the meat was acquired has been lost.
It may someday soon become necessary to replace the corn and soybean fields (see the latter below) in Indiana with crops that we can directly eat, and to therefore eat less meat, especially if we feel the moral obligation to get the most out of the landscape so that we can share our surplus food with starving people elsewhere (there are, shamefully, many such people). Further, if we used less land for agriculture, then more would be available for the many species of plants and animals which are grappling with extinction due to our grossly unnatural transformation of the landscape.
It has also been shown that a plant-based diet considerably reduces greenhouse gas emissions because less energy is required to get the food to the plate (i.e. less energy is required for farm equipment fuel, labor, and irrigation) and therefore is less of a threat to the Earth’s climate than is a meat-based diet (Eshel and Martin, 2006). These authors estimate that if all Americans consumed a plant-based diet, national greenhouse gas emissions would be lessened by six percent.
However, many scientists believe that meat consumption has been a very important part of our evolutionary past, so it makes perfect sense that we are programmed to savor the taste of meat (and maybe even make fun of vegetarians).
Consuming meat, and being predators, likely was a major cause of our large brains. Predators must be smart enough to catch their prey, whereas as herbivores need to be only smart enough to find plant material to eat (our language suggests this knowledge: ‘sly as a fox,’ ‘wily coyote’; ‘don’t be a sheep,’ ‘stupid cow’). Having predatory ancestors likely helped us on our way to becoming human. It is likely that protein-rich diets allowed our ancestors to allot more resources to brain material, which gradually led to us and our huge brains (and our exceptional, at least on Earth, cognitive abilities). Incidentally, plant-based diets can now provide, due to our advanced technologies, more than enough protein to fuel any human mind, without the cardiovascular disease that may accompany meat consumption.
So, I am not saying that eating meat is all bad (if my ancestors hadn’t, I probably wouldn’t be thinking about this stuff). If the laboratory production of meat becomes viable, then the issues that I have overviewed will not be a major problem. That said, many people wouldn’t want to eat meat created in a lab (this decision will have to be made, probably, within the next fifty years, I’d guess). Currently, not everyone can or should be a vegetarian, and many have livelihoods that are based on meat production, which complicates matters, but all of us should consider the environmental (and therefore ethical, because we all share this environment) implications of consuming meat and other animal products like eggs and dairy. And all of us should do our best to be sure that what we eat (and the people who provided what we eat) is not abused before it is eaten, for obvious moral reasons, considering that we are all in this together.
And that is my answer!!!
If you have any conflicting or like opinions, feel free to share in the comments section!
Eshel, G., and Martin, P.A. (2006). Diet, energy, and global warming. Earth Interact. 10, 1–17.