Final answer:
In the U.S., more energy is used to produce and distribute food than the energy received from consuming the food. This includes energy for agriculture, transportation, and dealing with food waste. The energy input to output ratio is approximately 10:1, which has broader consequences for environmental impact and health.
Step-by-step explanation:
In the United States, the energy put into producing food outweighs the energy we get from consuming it. Modern agricultural practices require that for each kilocalorie of food consumed, approximately 10 kilocalories of energy input is needed. This means that a typical 2,100 kcal/day diet demands about 24 kWh of energy input, highlighting the substantial energy commitment necessary for food production compared to the energy we derive from the food itself.
Moreover, when considering how energy is used in livestock and poultry production, directly consuming the plants that feed these animals would be more energy-efficient. The conversion of plants to meat involves a low efficiency, rendering animal agriculture a net energy drain. To further exacerbate the issue, there's considerable food waste in the U.S., with approximately 1.8 kcal of food produced for every 1 kcal consumed, due to waste in restaurants, cafeterias, and stores.
It's important to note that the abundance of food has also affected food prices and dietary preferences, with some nutritious foods being more expensive, and a trend towards higher caloric intake from fats and proteins being observed as incomes rise. These trends have implications for global food production, as well as health outcomes, such as obesity rates.