Before you purge the cupboards of crackers and toss out everything in the fridge that isn’t celery in preparation for a new diet, you’ll want to pause long enough to take note of a new study. While it’s tempting to banish carbs completely, as many trendy diets advocate, a team at Tufts University in Boston has found that people who ate whole grains absorbed fewer calories from their food—an amount equivalent to nearly a cookie a day.
In the study, published in the American Journal of Clinical Nutrition, the Tufts researcher team found that swapping white rice for brown rice and whole grain cereal for more sugary options, increased calorie loss. Before you scoff and say—they’d lose even more if they cut carbs completely!—it might surprise you to learn that the whole grains they ate reduced the amount of calories they absorbed during digestion and also sped up their metabolism. (Find out why low-carb diets aren’t the answer.)
The researchers observed 81 men and women, aged 40 to 65, over a six-week study period. Participants were divided into two groups—those eating whole grains such as whole wheat bread, brown rice, and whole-grain pasta, and those eating more refined grains, including white bread, white rice, and regular pasta. They even underwent blood testing to make sure they weren’t straying from their assigned grains group. Tufts researchers provided all of the food for study participants so they could ensure that nothing else in their diet was changed except for the type of grains, and it’s worth noting that participants consumed much of the sugar and fat that an American diet usually includes.
At the end of the six weeks, Dr. Karl reported that the differences in calorie intake were measurable. The men and women who ate whole grains took in fewer calories a day than their counterparts who ate the same diet with American-style processed grains. The change in grains could add up to a loss of 5 pounds a year, though researchers weren’t measuring weight loss in this investigation. “People who were eating whole grains compared to people who were eating refined grains had a larger excretion of energy in the stools, so they were not absorbing as many of the calories that they were eating,” Phil Karl, PhD, who worked on the study, told NBC News. “They were going more, pooping more frequently, and in larger volumes. Potentially, they were not digesting as much energy from their diet.”
The research team attributes that effect to the fact that the greater amount of fiber in whole grains is not digested, and in turn, it can pull out other undigested foods with it, according to Dr. Karl.
“There was about 100 calories per day difference in energy deficit in the whole grain group,” Dr. Karl said. “There also seemed to be a slight difference in resting metabolism, how many calories a person burns while sitting still, as the whole-grain eaters had a slightly faster metabolism.”
Researchers admit that “human weight loss and weight gain is not an exact science,” but their findings could prove significant in helping people slow the steady weight gain that often occurs as we age.
In order to take advantage of the benefits of the study for yourself, simply swap out your favorite carbohydrates for whole grain versions and include more whole grains in your diet in your general. Go for brown rice, barley, buckwheat, bulgur, whole oats, whole grain oatmeal, and even things like whole corn tortillas.(Also check out the ancient grains that are on their way to becoming the next quinoa.) Look for brands with “whole” in front of the first ingredient, and make sure they have at least three grams of fiber per serving. Here are more tips on how to include whole grains in your diet.