Possibly a confusing post title. and yawn inducing grimace for those of you without a science background! Simply put, every time we convert energy (in this case by consuming plant or animal life) we lose efficiency. We happen to be vegetarians, for ethical reasons, and so our animals will live out their life spans and return to the soil; where their nutrients will once again be part of the process that has gone on for millions of years. Now this isn't a sermon on "veg is better than meat", we leave each and all to decide how they wish to approach that question, but Trophic conversion is important from a sustainability issue, given ever increasing populations, countries aspiring to first world status, and looming climate changes.
Understanding the trade-offs in water usage, protein and other nutritional factors, cultivation, and the use of pesticides, between different crops and food chain elements, is more than an esoteric discussion for scientists. As farmers, even on a small scale, it is essential to understand the impact that lifestyle has on food production and, in our "designer-led" society where appearance seems to matter so much more than substance, what pitfalls that might lead us to in the future.