What is a Calorie?

In Good Calories, Bad Calories, award-winning science writer Gary Taubes shows us that almost everything we believe about the nature of a healthy diet is wrong.

We hear about calories all the time: How many calories are in this cookie? How many are burned by doing 100 jumping jacks, or long-distance running, or fidgeting? But what is a calorie, really? And how many of them do we actually need?

Emma Bryce explains how a few different factors should go into determining the recommended amount f...