Your Favorite Junk Food Could Be Feeding More Than Cravings

Dramatically reducing ultra-processed foods may ease symptoms of depression and anxiety, a small pilot study suggests, adding to evidence that diet and gut health may influence mental well-being.

Researchers reported Sept. 23 in JAMA Psychiatry that participants experienced less depression and anxiety after reducing their ultra-processed food intake by more than 85 percent.

The findings suggest that junk food “may harm your gut in ways that ripple up to your brain,” lead researcher Dr. Nyasha Chagwedera, an assistant professor of psychiatry and behavioral sciences at the University of California, San Francisco, said in a news release.

How the Pilot Study Worked

For the study, researchers recruited 20 participants diagnosed with depression. Among them, 14 also had anxiety.

The patients were all overweight or obese and suffered from at least one metabolic disorder, including high blood pressure, diabetes, or elevated cholesterol.

Participants were divided into two groups. One group continued their regular diet for four weeks, while the other shifted to a diet low in ultra-processed foods. After four weeks, the groups swapped diets.

RELATED: What Too Much Junk Food Could Be Doing to Your Bones

What Counts as Ultra-Processed Food?

Ultra-processed foods are made mostly from substances extracted from whole foods, like saturated fats, starches and added sugars. They also contain a wide variety of additives to make them tastier, more attractive, and shelf-stable, including colors, emulsifiers, flavors, and stabilizers.

Examples include packaged baked goods, sugary cereals, ready-to-eat or ready-to-heat products, and deli cold cuts.

These foods are designed to push people’s buttons in ways intended to promote overeating, Chagwedera said.

“Ultra-processed food triggers dopamine, the pleasure hormone, which promotes craving,” Chagwedera said. “Food companies work with scientists to find just the right amount of sugar, salt and fat that make you want to eat more and more.”

Reducing Intake and Measuring the Results

People assigned to eat less ultra-processed food shopped for their own meals, with guidance from researchers.

“Reducing the amount of ultra-processed food in our diet can be challenging, because it’s highly palatable, cheap and convenient,” Chagwedera said.

Results showed that when people cut down on ultra-processed food, they scored significantly lower on three measures for depression. They also had modestly improved anxiety scores.

RELATED: 10 Ways To Easily Kick Processed Foods Out Of Your Diet

What the Findings Could Mean for Depression

Depression is more than feeling sad or having a bad day. It’s a serious mental health condition that can affect mood, sleep, appetite, energy, concentration and the ability to enjoy activities that once felt meaningful.

For people living with depression, those symptoms can also make everyday tasks—including grocery shopping, meal planning and cooking—feel overwhelming. That can make convenient, ready-to-eat foods an especially appealing option.

The new study adds to growing research exploring whether what we eat may influence depression symptoms. Participants who significantly reduced their ultra-processed food intake experienced improvements in several measures of depression, suggesting that dietary changes could potentially play a role in supporting mental health.

However, the findings do not mean that ultra-processed foods cause depression or that changing your diet can cure it. The study included only 20 people, all of whom had depression along with overweight or obesity and at least one metabolic condition. More research is needed to determine whether similar benefits would occur in larger and more diverse groups of people.

If you are living with depression, nutrition can be one part of a broader approach to mental health. Treatment may include psychotherapy, medication, lifestyle changes or a combination of approaches, depending on your needs. If depression symptoms are interfering with daily life, talking with a healthcare professional is an important step.

Dietary changes also don’t have to be drastic. Instead of trying to eliminate every ultra-processed food, consider adding more whole or minimally processed foods to your meals and making gradual swaps that are realistic for your budget, culture and lifestyle.

Why the Gut-Brain Connection May Matter

The link between junk food and depression might be explained by a “leaky, out-of-balance gut,” Chagwedera said.

Ultra-processed foods can damage the gut’s protective lining, she said.

“This gut damage can create low-grade, chronic inflammation throughout the body that either directly causes depression or makes people more vulnerable to it,” Chagwedera said.

How to Reduce Ultra-Processed Food Consumption

Reducing ultra-processed foods doesn’t have to be an all-or-nothing effort. Start with small, gradual changes. Johns Hopkins University recommends these steps:

• Keep plenty of healthy foods at home, and try not to buy UPFs at the grocery store.
• Try preparing meals at home in advance that use less processed foods.
• Read nutrition labels and ingredient lists before you buy, and look for foods with only a few pronounceable, recognizable ingredients.  
• Try replacing an ultra-processed food with fruit or vegetables. Use minimally processed frozen or canned options if fresh fruit or vegetables aren’t available.
• Replace sugary beverages with water.
• Choose whole grains, like whole wheat bread, over processed grains like white bread.
• Make a homemade version of a processed food, like sweet potato chips, healthy muffins, bread, or salad dressings.
• Choose healthier menu options when eating out, like salmon with steamed vegetables instead of a hamburger.

What Comes Next

The results are encouraging, but the study was small and designed primarily to test feasibility—not to prove that dietary changes treat depression or anxiety. Larger, longer trials are needed to determine whether the improvements hold across broader groups of patients.

For now, the clearest conclusion is that a larger-scale trial is practical—a key first step toward testing whether cutting ultra-processed foods can become a useful complement to established mental health care, senior researcher Dr. Andrew Krystal, a distinguished professor of psychiatry and behavioral sciences and neurology at the University of California, San Francisco, said in a news release.