Final answer:
Vegetarian diets are more energy-efficient due to the lower energy costs in producing plant-based foods compared to the higher energy input required for meat production, reflecting a reduced energy footprint and contributing to sustainable food practices.
Step-by-step explanation:
Energy Efficiency of Vegetarian Diets
A vegetarian diet is considered more energy-efficient than a diet based on meat because of the energy use and conversion inefficiencies in the production of meat. Warm-blooded animals like cattle have a low Net Primary Productivity (NPE), meaning much of the energy from the crops they consume is lost rather than converted into edible meat. For example, producing 1000 dietary calories of beef may cost around $0.19, while the same calorie amount from corn or soybeans is about $0.01. This energy inefficiency is represented in the dietary energy factor, which suggests that vegetarian diets require less energy to sustain compared to meat-based diets. To illustrate, the typical American diet uses about 24 kWh/day, while a vegan diet only requires 4 kWh/day, and a lacto-ovo vegetarian diet (including dairy and eggs) is about 9 kWh/day.