These Foods May Raise Your Depression Risk

It’s no secret that what we eat affects our bodies. We’ve known for years that diets high in sugar, unhealthy fats and other ingredients found in ultra-processed foods (UPF) can be linked to physical health issues like heart disease and diabetes. But recently, science has started to uncover a much more complex relationship between our diet and our minds.

The prevalence of these UPFs—think soft drinks, certain packaged snacks and mass-produced breads—has skyrocketed in many countries. In countries like Australia, UPFs now account for nearly 40% of the average adult diet. These items can be low in nutrients but high in ingredients like added sugar and unhealthy fats. While their convenience is undeniable, new research published in Frontiers in Nutrition suggests the cost to our mental health might be higher than we realize.

How Was This Study Conducted?

To understand the scope of the problem, researchers conducted a comprehensive scoping review, which is a systematic analysis of existing literature to map out what we currently know about a specific topic.

The researchers searched major medical databases, with the goal of finding literature that intersected three core concepts: ultra-processed foods, mental health disorders and lipid (fat) metabolism.

They applied strict criteria for inclusion. Studies had to compare high versus low levels of UPF consumption and their effect on psychiatric disorders, or investigate the biological mechanisms connecting UPFs to lipid dysregulation in the brain. They included human studies across all ages and demographics, as well as animal studies to better understand the biological mechanisms at play. Ultimately, 123 studies were included in the final review, providing a robust overview of the current scientific landscape.

What Did the Study Find?

The review found that ultra-processed food (UPF) consumption is closely linked to increases in the global mental health burden. In particular, the study highlighted that higher UPF intake is associated with a greater risk of common mental health conditions that contribute significantly to this burden worldwide—most notably, depression. The authors explain that depression alone makes up a large portion of global mental health challenges, and the strongest evidence in the review pointed to a “dose-dependent” association: the more UPFs people consumed, the more likely they were to experience depressive symptoms.

Foods such as sugar-sweetened beverages, fast food and fried foods showed the clearest connections with increased risk. The study also pointed out that UPFs are linked to other common conditions:

• Anxiety: While findings were mixed, several studies linked high UPF intake, particularly from artificial sweeteners and processed meats, to increased anxiety symptoms.
• Eating Disorders: There was a strong correlation between UPF consumption and eating disorders like binge-eating disorder and bulimia. The hyper-palatability of these foods may trigger addiction-like reward responses in the brain, similar to substance use disorders.

A critical finding of this review was the potential mechanism behind these risks: lipid dysregulation. The brain is largely made of fat, and it relies on healthy lipids (fats) for cell membrane integrity and signaling. UPFs are often high in trans fats and low in essential omega-3 fatty acids. This imbalance can lead to neuroinflammation (inflammation in the brain), oxidative stress and disruptions in neurotransmitters like serotonin and dopamine. Essentially, the review suggests that UPFs might be physically altering the structure and function of our brain cells.

Limitations

While these findings are significant, it is important to view them with a scientific lens. The review authors noted several limitations. First, the majority of the studies reviewed were cross-sectional. This means they looked at a population at a single point in time. While they can show a correlation (e.g., people who eat more UPFs tend to be more depressed), they cannot definitively prove causation (that the UPFs caused the depression).

Second, there was variability in how foods were classified. Not every study used the standard NOVA classification system for processed foods, making direct comparisons difficult. Furthermore, many studies relied on self-reported data, which can be prone to memory errors. And while animal studies provided strong evidence for the biological mechanisms (like lipid dysregulation), findings in mice don’t always translate perfectly to humans. Longitudinal studies, which follow people over many years, are needed to confirm the direction of these relationships.

How Does This Apply to Real Life?

Despite the limitations, the plausibility of these findings is strong enough to warrant attention to our daily habits. This isn’t about fear-mongering or striving for a “perfect” diet, but about making informed choices for brain health. And this study doesn’t mean you need to forego ultra-processed foods entirely, though you may want to cut back on how often you eat them—especially if you’re opting for those that are high in sugar.

Here are a few practical steps you can take:

• Prioritize whole foods. Focus on foods like fruits, vegetables, whole grains, nuts and lean proteins. These foods provide nutrients and, in some cases, healthy fats your brain needs to function optimally.
• Swap, don’t stop. If you need a snack, satisfy your hunger with a less processed option. Swap packaged chips for air-popped popcorn or nuts. Those small changes add up.
• Skip your usual soda. Instead of a sugary soda, try sparkling water with lemon or a splash of another favorite juice. You might also opt for coffee with less sweetened creamer or coffee syrup in the morning.

Our Expert Take

This scoping review published in Frontiers in Nutrition provides a synthesis of how ultra-processed foods may be impacting our mental health through certain biological pathways, particularly by interfering with how our brains process lipids. By analyzing over 120 studies, the researchers highlighted consistent associations between high UPF intake and conditions like depression, anxiety and eating disorders.

While we await more long-term research to solidify the causal links, the current evidence offers a powerful motivation to reconsider what we put on our plates. Nourishing our bodies with minimally processed, nutrient-dense foods may be a vital component of caring for our minds.