Why are short food chain better?
Going up each level of the pyramid, less and less energy is available for the organisms at the next level as we go down the food chain. The number of organisms the pyramid can support is small. Hence, food chains are generally short. This explains why there are typically more prey than predators in a community. A shorter food chain means more energy is available to the final consumer beacuse less energy is lost to the environment.

eg,
more energy will be available to a man if he feeds directly on crop plants grown on a given area, rather than eating the cattle that feed on his crop plants.