New Study Finds 57% of U.S. Adults Consume Pro-Inflammatory Diets

A recent large-scale analysis has found that the majority of Americans are eating an inflammatory diet, increasing their risk for a range of health problems, including heart disease, Type 2 diabetes, and cancer.

Conducted by researchers at Ohio State University’s College of Public Health, the analysis looked at the self-reported diets of a nationally representative group of more than 34,000 American adults who participated in the National Health and Nutrition Examination Survey. Researchers scored each participant’s diet using the dietary inflammatory index (DII), a tool designed to assess inflammation in the diet. The index ranges from -9 to 8, with a score of 0 indicating a neutral diet, lower than 0 indicating an anti-inflammatory diet, and higher than 0 indicating a pro-inflammatory diet.

After completing their assessment, they found that 57% of participants had inflammatory diets. Thirty-four percent had anti-inflammatory diets, and the remaining 9% ate diets with a neutral impact on inflammation. The findings were published in the journal Public Health Nutrition on Sept. 27.

“The overall balance of diet is most important,” the study’s lead author, Rachel Meadows, said in a statement. “Even if you’re eating enough fruits or vegetables, if you’re having too much alcohol or red meat, then your overall diet can still be pro-inflammatory.”

Because factors such as financial adversity can limit access to fruits, vegetables, and other healthy foods, Meadows’ team was also interested in identifying how socio-economic factors correlated with dietary inflammation. They found that Black Americans, men, younger adults, and people with lower education and income were more likely than average to have pro-inflammatory diets.

First developed a decade ago, the dietary inflammatory index (DII) is based on more than 50 years of scientific research around the ways foods and other dietary components, including alcohol, spices, and tea, influence inflammatory markers, such as C-reactive protein.

According to the DII, garlic, turmeric, ginger, and high-fiber foods (i.e., whole grains, fruits, beans, and vegetables) are highly anti-inflammatory. By contrast, the DII indicates that meat, vegetable oils, and refined carbohydrates are pro-inflammatory.

A 2021 umbrella review including data from more than 4 million participants found that the DII was a useful predictor of health outcomes, with pro-inflammatory diets leading to higher rates of chronic diseases.

“Moving toward a diet with less inflammation could have a positive impact on a number of chronic conditions, including diabetes, cardiovascular disease and even depression and other mental health conditions,” Meadows said.

Inflammation is a necessary tool for healing the body from infection and injury, but excess inflammation can lead to serious health problems over time. Healthy lifestyle choices can prevent and mitigate this type of inflammation.

“There are a lot of factors that contribute to chronic inflammation, and they all interact—even sleep is a key component,” said Meadows. “Diet can be used as a tool to combat that.”

To learn more about a whole-food, plant-based diet, visit our Plant-Based Primer. For meal-planning support, check out Forks Meal Planner, FOK’s easy weekly meal-planning tool to keep you on a healthy plant-based path.