The Oil Drum post some interesting data on the energy input required to produce different kinds of foods; I threw them into bar chart form and it sure looks like Graham Hill should be pitching the idea of a Weekday Vegan rather than a Weekday Vegetarian; when it comes to the energy required to produce it, cheese is higher than chicken. Do we have to give it up too?

Not necessarily. Their second table looks at the comparative efficiency of producing foods; they note:

Roughly twenty-five times more energy is required to produce one calorie of beef than to produce one calorie of corn for human consumption. Dairy products are actually fairly energy efficient, as they are very dense in calories. Vegans may indeed be able to boast that their diets use 90% less energy than the average American's, and even those who eat only eggs and dairy can lay claim to significant energy efficiency.

So cheese isn't so bad, because it packs so many calories per pound. Perhaps weekday vegetarianism is enough of a step. More at the Oil Drum.