Decisions about the foods we eat boil down to much more than simply what tastes good. Our culture, lifestyle, income and access to healthy (or unhealthy) foods all come into play. Understanding the factors that influence people’s food choices may prove helpful in leading people toward a better diet, a new study finds.

According to dietary guidelines, a healthy diet for adults should include at least 1½ to 2 cups per day of fruit; 2 to 3 cups per day of vegetables; a variety of legumes, nuts and whole grains; and limited amounts of fat and added sugar.

Over a third of Americans eat fast food on any given day, foods that are high calorie and of poor nutritional quality.

Unfortunately, only about one-tenth of Americans eat the recommended amounts of fruits and vegetables each day, data from the Centers for Disease Control show, and this puts them at risk for chronic diseases such as obesity, type 2 diabetes, heart disease and some forms of cancer. Over a third of Americans eat fast food on any given day, foods that are high calorie and of poor nutritional quality.

To get a better understanding of how four factors — education level, income level, access to grocery stores and access to fast food joints — affect people’s body mass index (BMI) and their intake of fruits, vegetables, fast food and soda, researchers from the University of Washington and Stanford University collected data from smartphone app food logs. Information from approximately two billion smartphone logs and 1½ million people from over 9,800 zip codes across the United States was gathered for about seven years. Participants were users of the My Fitness Pal app.

People who ate more fruits and vegetables and had a lower intake of soda and fast food had higher levels of education, better access to grocery stores and less access to fast food outlets. They were also less likely to be overweight.

Soda consumption was the lowest among Hispanics with higher educational attainment.

When these four factors were analyzed across white, Black and Hispanic ethnicities, some similarities and differences emerged:

  • Black populations with higher income levels ate fewer fruits and vegetables, had higher obesity rates and ate more fast food. But if they lived in areas with more access to grocery stores, Blacks ate two to three times more fresh fruit and vegetables and less fast food when compared to white people.
  • Blacks with both higher levels of education and better access to grocery stores also ate more fruits and vegetables.

  • Hispanics with more income and greater access to grocery stores also had a higher consumption of fruits and vegetables as well, but this relationship did not hold true in areas of predominantly white populations.
  • It didn’t matter if you were Black or White — people who lived in areas with fewer fast food outlets drank less soda, however, soda consumption was the lowest among Hispanics who had higher educational attainment.
  • People of all ethnicities with high levels of education were far less likely to have body mass index levels in the overweight or obese range.

Food choices are the result of what people like to eat based on their culture, family and what’s available in stores their neighborhoods, as these findings make clear. So, in order to be effective, programs designed to help people to make better choices need to reflect this. The programs have to be tailored to certain populations and locales. A one-size-fits-all approach to achieve healthy change isn’t the answer, even if some changes — like drinking fewer sugar-sweetened beverages — are universally beneficial.

The study is published in Nature Communications.