When it comes to addressing blood pressure, blood sugar and waist size, some people might think that means taking medication. But there is actually a much simpler way: Eat more whole grain foods.

Middle-aged and older adults who consumed at least three daily servings of whole grains had smaller increases in these three health indicators than people who ate fewer whole grains. That’s the conclusion by Tufts University scientists, who studied whole- and refined-grain consumption among more than 3,000 people over a nearly 20-year period.

For each four-year interval in the study, the contrasts were stark. People who very few whole grains gained more than one inch in waist size. Those who consumed the most whole grains gained less than half an inch. Likewise, blood sugar and blood pressure levels were higher among people who ate fewer whole grains.

As the researchers noted, it’s not an all-or-nothing arrangement. As whole grain consumption grew incrementally among the study participants, so did the positive health benefits. All of that suggests that whole grains are one way to help manage blood pressure and blood sugar over time.

So how much whole grain should you eat? Among the study participants, consumption ranged from less than a half serving per day to three or more servings. One serving can include a half-cup of brown rice or rolled oats — or a slice of whole-grain bread. An easy way to make the switch can be to swap out refined grains such as pasta, white bread or traditional cereal for their whole-grain counterparts.

As the researchers noted, even small dietary changes can make a difference over time.