There's a classic bluegrass fiddle/mando tune called Whiskey For Breakfast. I've played the song dozens of times, but only a few occasions have I actually had whiskey for breakfast. Honestly, I prefer granola or a fried egg and toast.
Anyway, as it turns out, no matter what I have for breakfast, whether it be of the free-range hormone-free variety, or of the twelve-year-old black label variety, what I'm really eating is petroleum.
This recent article from the SF Chron. does a great job to illustrate the connection between our diets and the fossil-fuel-derived energetic requirements for providing us with nutrition. Apparently it takes about 7 calories of fossil energy to produce 1 calorie of food energy -- not such a good tradeoff. This makes clear the urgency of humans' transition to some kind of sustainable food system.