When looking at all teenage girls together without considering where they were in their menstrual cycle, eating more processed foods didn't consistently change how dense their breast tissue looked on scans.

When teenage girls eat more processed foods, their breast tissue might look denser on scans only during the first half of their menstrual cycle, but this doesn't happen all the time or during other parts of the cycle.

When looking at how much of the total calories came from processed foods (instead of how many grams), there was no consistent link to breast density at any point in the menstrual cycle.

When looking at how much of the total calories came from processed foods (instead of how many grams), there was no consistent link to breast density at any point in the menstrual cycle.

Whether eating processed foods affects breast density seems to depend on what part of the menstrual cycle a girl is in - it only shows an effect during the first half of the cycle, not the second half.

The effect of processed foods on breast density during the first half of the menstrual cycle only happened at medium levels of consumption, not at the highest levels.