The solution to the food/energy/whatever crisis

I've been thinking about this food waste problem, because I want to do my bit to save fuel, or the economy, or the Ethiopians, or whatever it is one saves by not casting out unwanted food (bearing in mind that it is also a sin to be fat). What we require is an engine that can take in large quantities of stale food continuously, without developing a blockage, and convert it to kinetic energy. The solution already exists: it is called a Dog. All we need is some really big dogs and a lot more treadmills.