The average American eats out about six times a week, and a third eat at a fast food restaurant every single day. Eating out can be a recipe for nutritional disaster. Most meals eaten at restaurants or fast food joints are of poor dietary quality and provide excess calories, a new study finds.

Eating out has a huge impact on the overall diet quality of Americans and contributes to the number of people suffering with chronic diseases, most of which are diet-related.

Less than 0.1 percent — practically none — of all meals eaten out were of ideal nutritional quality.

Researchers at the Friedman School of Nutrition Science and Policy at Tufts University looked at information collected on over 35,000 adults in the 2003-2016 National Health and Nutrition Examination Survey (NHANES) who said they ate at full-service restaurants or fast-food restaurants, including pizza shops. The nutritional quality of their meals out was evaluated using the American Heart Association 2020 diet score, along with the USDA Food Patterns Equivalents Database and MyPyramid Equivalents Database measures of food groups and nutrients.

The results were dismal.

Seventy percent of the meals eaten at fast-food outlets were deemed to be of poor dietary quality, an improvement from the 75 percent reported in the 2003-2004 survey, but still not good. About half of meals eaten at full-service restaurants didn’t stack up to nutritional guidelines, about the same as in the previous survey. The rest of the meals were considered to be of intermediate quality. Less than 0.1 percent — practically none — of all meals eaten out were of ideal nutritional quality.

The extent to which Americans relied on restaurants is concerning. Meals eaten out represented 21 percent of total calorie intake with full-service restaurants meals accounting for nine percent of total calories eaten and fast-food restaurants at 12 percent. On average, Americans get one of every five calories from restaurant meals. The number of breakfast meals consumed at fast-food places doubled from four percent to almost eight percent of all breakfast meals eaten.

Several disparities were found in the study. The nutritional quality of fast-food meals eaten by non-Hispanic whites and Mexican-Americans improved between studies, but no change was seen in the quality of fast-food meals eaten by non-Hispanic blacks. In addition, the dietary quality of fast-food meals eaten by people with a college degree decreased from 74 percent to 60 percent, while that number stayed at around 76 percent for people without a high school diploma.

“Our food is the number one cause of poor health in the country, representing a tremendous opportunity to reduce diet-related illness and associated healthcare spending,” researcher, Dariush Mozaffarian, said in a statement. “At restaurants, two forces are at play: what's available on the menu, and what Americans are actually selecting. Efforts from the restaurant industry, consumers, advocacy groups and governments should focus on both these areas.”

The best way to improve restaurant and fast-food meals is to add more grains, nuts, legumes, fish, fruits and vegetables to meals and reduce the amount of salt in them, the researchers say. Since such sweeping changes in the restaurant industry are unlikely anytime soon, cooking healthy meals and eating at home more often would be the most beneficial way to improve a person’s diet.

The study was published in The Journal of Nutrition.