Find out how nutrition science has evolved in the past decade. Here's what we know now—and didn’t then.
"Such a well sourced article Karen! It's very interesting to see how the common-knowledge assumptions change over time, thanks for the read! "
3. A calorie isn’t just a calorie
You’ve heard it a million times: to stay weight-stable, calories in must equal calories out. Now we’re learning that may not always be the case. In a 2010 Food & Nutrition Research study, researchers asked volunteers to eat either a sandwich made from multigrain bread and Cheddar cheese or a white bread and processed cheese sandwich. When the researchers measured how much energy it took to digest and absorb each of the sandwiches, they found the volunteers used nearly twice as many calories to break down the multigrain sandwich. The reason: our bodies handle processed and unprocessed carbohydrates differently. “When you use a machine to strip away the bran, husk and fiber from carbohydrates, that machine is essentially expending energy that your body would normally use to break down those food components,” says study co-author Jonathan Wright, Ph.D., a professor of biology at Pomona College.