Older kids (9–10 years old) who eat more packaged and processed foods may have higher levels of a body chemical linked to inflammation, but younger kids don’t show the same pattern.

Kids who eat a lot of packaged snacks, sugary drinks, and processed meats may have slightly higher levels of a body chemical that signals inflammation, especially if they eat more of these foods.

Kids who eat a lot of processed foods may have higher levels of a chemical that tries to calm down inflammation, as if their body is working extra hard to balance things out.

Eating more processed foods doesn’t seem to change most of the body’s inflammation signals in kids, except maybe for a couple of them.

Eating more or fewer AGEs—chemicals found in grilled or fried foods—for six weeks doesn’t seem to change inflammation levels in healthy people aged 50 to 69, so short-term diet changes like this probably don’t affect body-wide inflammation.

Eating lots of ultra-processed foods is linked to having several chronic diseases at once, feeling weaker, living with less quality of life, and having long-lasting body damage — especially in older people.