Is driving more eco friendly than walking?
Discussion
http://www.bbc.co.uk/blogs/ethicalman/2009/03/ethi...
bbc news said:
Brad explains that the average person uses about 100 calories per mile walking at 3 mph - 300 calories per hour. By comparison sitting burns 80 calories an hour. In other words, walking three miles takes an extra 220 calories.
Now, a (US) gallon of gasoline has about 31,500 calories so the conclusion might be that a human walking gets around 400 mpg. But, as Brad points out, that ignores the fossil fuels that go into producing the food we eat.
Brad claims US agriculture uses about 400 gasoline-gallon equivalents per American per year (if anyone can source this figure I would be very grateful). So that is 1.1 gallons a day to produce the 2700 calories that form the average American's diet or 10 calories of fossil fuel for each calorie of food consumed. That is right: 10 fuel calories for each food calorie! It is a shocking statistic isn't it?
Justin ruins his suitYou will have guessed where this is going: walking 3 miles uses 220 extra calories over sitting, but sucks up 2,200 calories of fossil fuel. This means you get just 42 mpg as you stroll. Some small cars are more efficient.
And, if you eat a lot of burgers, the figures are even worse. Your fuel consumption rises dramatically because 40 calories of fuel energy are used per calorie of beef. If you only ate beef you would not only be very unhealthy, you would get just 10 mpg as you walked, worse than a Humvee!
Now, a (US) gallon of gasoline has about 31,500 calories so the conclusion might be that a human walking gets around 400 mpg. But, as Brad points out, that ignores the fossil fuels that go into producing the food we eat.
Brad claims US agriculture uses about 400 gasoline-gallon equivalents per American per year (if anyone can source this figure I would be very grateful). So that is 1.1 gallons a day to produce the 2700 calories that form the average American's diet or 10 calories of fossil fuel for each calorie of food consumed. That is right: 10 fuel calories for each food calorie! It is a shocking statistic isn't it?
Justin ruins his suitYou will have guessed where this is going: walking 3 miles uses 220 extra calories over sitting, but sucks up 2,200 calories of fossil fuel. This means you get just 42 mpg as you stroll. Some small cars are more efficient.
And, if you eat a lot of burgers, the figures are even worse. Your fuel consumption rises dramatically because 40 calories of fuel energy are used per calorie of beef. If you only ate beef you would not only be very unhealthy, you would get just 10 mpg as you walked, worse than a Humvee!
Edited by peterh2 on Monday 16th March 23:43
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