You Can't Outrun a Bad Diet
A common misconception is that as long as you are physically active you can eat anything you want — “What’s another slice of pizza, I’ll walk it off tomorrow!”
“To truly live a healthful lifestyle requires both diet and exercise,” said Deborah Rohm Young, Ph.D., director of behavior research at Kaiser Permanente Southern California. “One can’t take care of the other.”
For example, walking three miles burns around 250 to 300 calories. That’s not much when a restaurant meal can easily exceed 1,000 calories, Young said.
One reason is that exercise and diet play different roles in maintaining health, said Young, who is also the immediate past chair of the Physical Activity Committee for the American Heart Associations’ Council on Lifestyle and Cardiometabolic Health.
“The benefits of each work on different mechanisms of the body,” Young said. “It’s rare to lose weight on an exercise-only program.”
Nearly 70 percent of American adults are either overweight or obese, and less than half of U.S. adults meet the recommended guidelines for physical activity (at least 150 minutes of moderate physical activity or 75 minutes of vigorous physical activity each week).
While exercise is important for maintaining several different components of overall health, the impact exercise can have is limited if changes aren’t made to a bad diet for people trying to lose weight.
Physical activity has many benefits beyond weight control, including strengthening muscles, bone density, diabetes management and improving mental health. A heart-healthy lifestyle including physical activity and a healthy diet can help reduce heart disease risk factors such as high cholesterol or high blood pressure.
And focusing solely on calories is also incomplete for a healthy lifestyle, because not all calories are equal. For example, the calories in a bag of chips don’t include the vitamins and nutrients of an equal number of calories of fruits or vegetables.
“It doesn’t matter what your weight status is,” Dr. Young said. “It’s important to eat a healthful diet.” But moderation is key.
“There’s nothing wrong with desserts and chips and other junk food if it’s in moderation,” she said. “It becomes a problem when that type of food becomes the rule rather than the exception.”