How scientists spot ultra-processed foods in your body

If you have ever wondered how much of your diet comes from ultra-processed foods, you are not alone—and now, scientists can actually measure it! Exciting new research published in PLOS Medicine shows that by looking at molecules in your urine and blood, doctors can tell how much packaged, factory-made food you eat every day (read the full study here). This breakthrough could help connect our eating habits to health problems like diabetes and cancer, and it gives us a more reliable way to track what we really eat.

What are ultra-processed foods and why do they matter?

Ultra-processed foods are not just cookies and chips. They include a huge range of industrially made foods, such as sweetened yogurts, ready-to-eat breads, and even some breakfast cereals. These foods are made in factories and often contain added sugars, fats, and special chemicals called emulsifiers that you would not find in your kitchen at home. Scientists have already found that eating a lot of these foods is linked to health problems like obesity, heart disease, diabetes, and even some cancers (see detailed findings).

How do scientists figure out what you really eat?

In the past, researchers mostly asked people to remember and write down what they ate. But let’s be honest—who remembers every snack or bite of cake they had last week? This made it hard to get accurate results. That’s why scientists started looking for clues in our bodies. When we eat food, our bodies break it down into smaller molecules called metabolites, which then show up in our blood and urine. By studying these metabolites, scientists can get a much clearer picture of what we have been eating.

For more on why our brains remember some foods better than others, you can check out this helpful summary: why we crave sugar even when full.

Making invisible foods visible with health AI

In this recent study, scientists collected urine and blood samples from 718 healthy people between the ages of 50 and 74. These people also kept food diaries over a year, writing down everything they ate and drank. The researchers then used a type of health AI called “machine learning” to connect the types of foods people ate with the metabolites found in their samples (study details). On average, half of the energy in people’s diets came from ultra-processed foods, but some ate much more or much less.

What do these molecules really tell us?

The scientists discovered that people who ate more ultra-processed foods had more metabolites linked to higher risks of type 2 diabetes. They also found molecules in the urine that come from certain food packaging, showing how processed foods can affect us in unexpected ways. Plus, these people had fewer metabolites from healthy fruits and vegetables in their samples. This is important because it means scientists can now tell if a person eats mostly packaged foods or fresh produce, just by looking at their blood or urine.

If you have ever disliked certain foods, you might be interested to know there is science behind your taste preferences as well. For more on that, see why do we hate certain foods.

Why does this matter for your health?

Knowing what we really eat is key for understanding how diet affects our health. This new way of measuring diet can help doctors and scientists connect what we eat to diseases like diabetes, heart disease, and cancer much more accurately. It also means future studies will be more reliable, since they do not have to rely only on people remembering what they ate. With tools like SlothMD and new health AI, we are moving toward a future where everyone can get personal insights into their diet and health risks—making it easier to make healthier choices.

What it means for patients

If you are worried about how much ultra-processed food is in your diet, there is good news. As science gets better at measuring what we eat, you will have more accurate information about how your food choices affect your health. In the future, doctors may use these tests to help guide you toward healthier eating patterns. And with platforms like SlothMD, which help you keep track of your medical records and health data, you are even more empowered to take charge of your well-being.