How much junk food does an average American eat? A simple blood test has the answer

More than 57% of calories in the average American diet come from ultra-processed foods. These include chips, candy, soda, and ready-to-eat meals. Now, scientists have developed a blood test that can measure how much of this food a person really eats.

For years, researchers relied on food diaries and surveys to understand diets. But those methods are not always accurate. People forget, misreport, or don’t notice how much processed food they eat.

This new test changes that. Scientists can now find molecular markers in the blood that show how much ultra-processed food someone consumes. These markers include chemicals linked to additives like preservatives, artificial sweeteners, and colorings, all common in packaged and fast foods.



The research was published in PLOS Medicine and included hundreds of participants. Their blood samples were tested and compared with their reported diets. The results matched: the more processed food someone ate, the higher the levels of specific markers in their blood.


The test then gives each person a diet “score” based on the amount of ultra-processed food in their system. A higher score means a higher intake.


These high scores were also linked with serious health issues. People who consumed more ultra-processed food were more likely to have obesity, high blood sugar, high blood pressure, and other signs of poor metabolic health.


Dr. Marie-Pierre St-Onge, the study’s lead author, said this test could be a “game changer.” It provides an objective way to track diet quality, which could help doctors give better advice.

Nutrition scientists are hopeful the test can help in more than just research. It could be used in clinics, health programs, and even in public health surveys to get a better idea of how diet impacts long-term health.

However, the test is still new. Researchers say it needs more trials in different age groups and cultures before it becomes widely available.

Ultra-processed food is a growing global issue. But in the U.S., the numbers are especially high. Many people don’t realize just how much of their daily intake comes from these foods.

This test might help people better understand their diets and possibly lead them to make healthier choices. It could also help public health experts track diet trends and target the most at-risk communities.

In the future, your next health check-up might not just measure your cholesterol. It could also show you how much junk food is in your blood.