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	900 Miles per Gallon   (July 2, 2005) Since I do a lot of errands on my bicycle, I looked up how many calories riding a bike burns: about 500 calories an hour if you weigh about 175 pounds like I do and ride about 15 MPH (which is fairly fast, especially on a gentle upslope.) A pound of human fat contains about 3,500 calories (kilocalories, if you want to get technical, but let's just stick with the common useage). So riding at a good clip for seven hours would get you about 100 miles and burn one pound of fat. That's pretty efficient, isn't it? And sobering if you're trying to lose weight. If you bicycle an hour a day and don't eat anything extra, you can lose a pound of fat a week. (More if you add muscle mass, of course.) But bicycling 15 MPH for an hour is not that easy; you will definitely feel it by hour's end. We use the word "oil" for both petroleum and vegetable oil. As you might expect, they are both chains of hydrocarbons. As a result, a gallon of vegetable oil contains about the same calories as a gallon of gasoline (31,000 calories). This is why biodiesel fuel works as a replacement for petroleum diesel. Since a human can metabolize vegetable oil as fuel, then by simple extrapolation we can estimate that a human being could ride a bike 900 miles on a gallon of vegetable oil--or lose about nine pounds of human fat on the ride. That means that a mere 27 pounds of human fat would theoretically enable a rider to bike across the entire continental U.S. Alternatively, the rider could sip 3 gallons of vegetable oil to provide the same calories. Not a terribly enticing diet for a cross-country ride, but the take-away is simple: the human body is an extremely efficient engine, and it's difficult to burn the enormous quanitity of energy stored in 10 pounds of human fat. No wonder it's hard to lose weight, and no wonder our nation (and other developed nations) are suffering an epidemic of obesity. Here's a good calorie chart if you want to accurately calculate the burn rate for your daily exercise. The chart doesn't include cleaning house or gardening, but both qualify as moderately strenuous forms of exercise. * * * copyright © 2005 Charles Hugh Smith. All rights reserved in all media. I would be honored if you linked this wEssay to your site, or printed a copy for your own use. * * *
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