SEATTLE — Home is where the heart is — especially the healthy heart. Just by way of cooking your own food, you’re likely enjoying a healthier diet than those who rely on eating out, a new study finds. 

Researchers at the University of Washington interviewed 437 residents of nearby King County, asking them to fill out a questionnaire detailing their eating experiences. They compared this data to a metric devised by the USDA called the Healthy Eating Index.

The index, which evaluates one’s compliance with federal guidelines set for a healthy diet, is weighted on a 100-point scale.

The study showed that those who cooked at home about three times a week had an index score of 67. That score rose to 74, however, for individuals who doubled their at-home cooking rate to about six times a week. 

The home-cooked meals saw families enjoying diets lower in calories, sugar, and fat, the study determined, without adding any extra weight to a monthly food budget.

“By cooking more often at home, you have a better diet at no significant cost increase, while if you go out more, you have a less healthy diet at a higher cost,” notes Adam Drewnowski, the study’s lead researcher and a professor of epidemiology, in a university release. “The differences were significant, even with a relatively small study sample.”

With about half of all food expenditures being spent on food prepared outside the house, this study may help illuminate a potential cause for high rates of obesity and malnutrition— more than a third of Americans are obese, while only one-fifth meet the USDA’s dietary guidelines.

Americans generally work more than individuals from other Western nations, which may lead to what epidemiologists call “time poverty,” making the habit of cooking a luxury. Interestingly, the researchers didn’t find a correlation between income or education level and one’s propensity to eat out. Common wisdom would suggest that those who are poorer might resort to eating fast food.

While the study involved self-reporting— a methodology prone to faulty memory— Drewnowski explained that the vast majority of nutritional research is done this way.

The study’s relatively small sample size also warrants further examination. The findings are published in the American Journal of Preventive Medicine.

This study was originally published on March 17, 2017.