The Truth About Marathon Calorie Burn

Let’s say you’re training to run a marathon, and you want to be sure to give your body the calories it needs. Researchers at Tufts University have three words of advice: not to worry. A piece of toast will do.
The London Times reports on the Tufts’ researchers assertion that if you compare the calories burned by someone running the marathon to those burned by someone watching the event, the difference will be much less that most people expect. That’s because about 60 per cent of the calories we burn go to maintain basic
metabolic processes.
Another 10 per cent is burnt through the thermogenic effect of food —
simply the heat produced through digestion. Only the remaining 30 per
cent of calories we use are burnt off through physical exertion. By the end of the race, the experts say, runners will have burnt less than 1lb (0.45kg) of fat. Read more in the London Times.