The average American diet now gets more than half of its calories from ultra-processed foods, commonly referred to as junk food, including chips, candy, soda, and frozen dinners. For years, researchers have relied on food diaries to track what people eat. But those reports can be unreliable. Now, scientists have developed a blood test. It tells a more accurate story by detecting molecular traces of junk food in the bloodstream.
The new test identifies chemical markers in blood related to junk food consumption. These markers are linked to food additives like preservatives, artificial sweeteners, and colorings. These are all hallmarks of ultra-processed products.
Published in PLOS Medicine, the study involved hundreds of participants. Researchers compared the chemical markers in blood samples with self-reported diets. The results aligned: the more processed food people ate, the higher their marker levels. From there, each person received a diet “score” reflecting their intake of ultra-processed foods.
WHAT HIGH SCORES REALLY MEAN
These higher diet scores were not just numbers. They were strongly associated with obesity, high blood pressure, high blood sugar, and other signs of poor metabolic health, often attributed to junk food.
Dr. Marie-Pierre St-Onge, the study’s lead author, called the tool a “game changer”. She says it can help doctors better understand patients’ diets and offer more precise guidance for disease prevention.
BIG POTENTIAL, BUT MORE TESTING NEEDED
While promising, the test isn’t ready for routine use just yet. Scientists say more studies are needed to assess junk food consumption—especially across different age groups, cultures, and dietary habits.
Still, public health experts are hopeful. If rolled out more broadly, this tool could improve national nutrition data. This new test might also help target interventions. Additionally, it would give individuals a clearer picture of their real eating habits involving junk food.
TOWARD HEALTHIER CHOICES
Most people don’t realize how much ultra-processed food sneaks into their daily meals, often in the form of junk food. This new test may help change that.
Someday soon, a standard health check-up might not just measure cholesterol or blood sugar. It might also reveal how much junk food is lurking in your blood.