Diet Efficiency

I have been thinking lately about the efficiency of eating meat. I remember a rule of thumb from grade school science class that says at each step along the food chain only about 10% of the energy is passed along. So from the sun, to a food crop, to livestock to me is 100% x 0.1 x 0.1 x 0.1 = .1% efficient, on average. Not that great. And that's if I'm eating something that only eats plants. If I'm eating a secondary consumer of some kind, like a shark or an eagle, that's even worse. And if I eat a human cannibal, that adds at least two more steps in the chain dropping the efficiency down to about .001%.

Having read a recent Time article about biofuels, I have been thinking about what we use our arable land for. The headline of the article is a little alarmist, and erroneously suggests that biofuel proponents are somehow tricking people into hurting the environment, but the body of the article presents a pretty grim picture of the unintended consequences of using land inefficiently. I get most of my calories from fruits, vegetables and grains, but I probably have meat 5 or 6 days out of 7 for at least one meal. I like eating meat, but is it really worth the efficiency loss in the system? I don't know if I'm ready to cut meat completely out of my diet, but I can definitely stand to eat less of it.

Three hundred trout are needed to support one man for a year. The trout, in turn, must consume 90,000 frogs, that must consume 27 million grasshoppers that live off of 1,000 tons of grass.-- G. Tyler Miller, Jr., American Chemist (1971)

Grow food in dirt? Save time, eat dirt! --Goblin Farmer

I'll have to do some more research into how animal products (eggs, honey, milk, etc.) fit into the whole thing. I wonder if getting eggs out of a chicken for its whole lifetime, and then eating the chicken is more or less efficient than raising the chicken to a younger age and just eating it (fewer years of feeding, and fewer years of egg production). It would also need to be compared against just using the energy that made the chicken feed to make human feed instead. hmmm....