Eating ultra-processed foods every day is linked to higher rates of depression, anxiety, and cognitive decline in young adults.

Here’s the bottom line first: people who eat the most ultra-processed food — think nine or more servings a day — are about 50% more likely to develop depression than people who eat the least, according to research highlighted by Harvard Health. That’s not a small difference. That’s roughly the same odds gap as some well-known risk factors for mental health struggles.

Multiple large studies back this up. A major review of the research — pulling together data from many different studies — found that higher ultra-processed food consumption was associated with 53% higher odds of having depressive or anxiety symptoms. Separate research also found a link between eating lots of ultra-processed food and higher depressive symptoms. It’s important to note that these studies show associations — researchers can’t yet prove that ultra-processed food directly causes depression, but the pattern across many studies is consistent and hard to ignore.

Younger people seem to be especially affected. One review focused specifically on brain development found that ultra-processed foods have been linked to higher rates of mental disorders like depression and anxiety, plus inattention and hyperactivity, particularly in younger populations. So if you’re a teen or young adult, this isn’t just something to worry about later — it’s relevant right now, during a critical window for your brain.

What counts as ultra-processed? Think packaged snacks, fast food, sugary cereals, instant noodles, sodas, and most things with a long ingredient list full of things you can’t picture in a kitchen. You don’t have to eat perfectly to make a difference. Even cutting back — swapping one or two ultra-processed items a day for something closer to real food — moves you in the right direction.

The single most important thing to take away: your food choices aren’t just about your weight or your physical health. Research consistently links them to how your brain feels day to day. If your mood has been rough and your diet has been heavy on packaged and processed stuff, that connection is worth paying attention to.