View full lesson: http://ed.ted.com/lessons/what-is-a-calorie-emma-bryce We hear about calories all the time: How many calories are in this cookie? How many are burned by doing 100 jumping...
========== We hear about calories all the time.How many calories are in this cookie?How many are burned by 100 jumping jacks,or long distance running,or fidgeting?But what is a calorie, really,
and how many of them do we actually need?Calories are a way of keeping track
of the body's energy budget.A healthy balance occurs when we put in
about as much energy as we lose.If we consistently put more energy
into our bodies than we burn,the excess will gradually
be stored as fat in our cells,and we'll gain weight.If we burn off more energy
than we replenish, we'll lose weight.So we have to be able
to measure the energy we consume and use,and we do so with a unit
called the calorie.One calorie, the kind we measure in food,
also called a large calorie,is defined...
