Emerging research shows that diets high in ultra‑processed foods (UPFs), like sugary drinks, packaged snacks, and ready-made meals, are consistently linked to a greater risk of depression. Multiple large studies, found increased odds of depression among the highest UPF consumers. Scientists now suspect several biological pathways could explain this link including chronic inflammation, gut‑brain disruptions, and the effects of additives and blood‑sugar spikes. Below, we unpack the evidence, mechanisms, and practical steps to cut back.

What Counts as an Ultra‑Processed Food?

Ultra‑processed foods are industrial formulations made mostly from extracted or refined ingredients, with little or no whole food left. They’re engineered to be hyper‑palatable and shelf‑stable, often containing:

• Added sugars (high‑fructose corn syrup, dextrose)

• Unfamiliar additives (emulsifiers, artificial sweeteners)

• Flavour enhancers & colors

• Multiple processing steps

These products now make up over half of daily calories in many Western diets, with the USA leading at almost 60% of daily energy intake being composed of UPFs. The rates in Canada are on the rise too with daily intake just shy of 50%.

Big Studies, Bigger Findings

Research consistently shows a dose‑response link between ultra‑processed food intake and depression. For example, a landmark 2023 JAMA Network Open cohort of over 31,000 U.S. women followed for 14 years found that those in the highest quintile of UPF consumption had a 49% greater risk of developing depression compared to the lowest consumers. Building on this, an umbrella review in BMJ (2023) that synthesized nine cohort studies with more than nine million participants reported a 22% increase in the odds of incident depressive outcomes among high UPF eaters. Similarly, a 2024 prospective study of Australians aged 70 and older showed that those in the top quartile of UPF intake experienced a 11% higher hazard of experiencing depressive symptoms over eight years. Finally, a 2025 meta‑analysis covering observational studies reinforced this pattern, finding that the highest UPF consumers had 44% increased odds of depressive symptoms, 48% increased odds of anxiety symptoms, and a 22% increased risk of subsequent depression.

Together, these results underscore a clear, consistent message: every step up the UPF ladder translates into a meaningful jump in depression risk.

Why UPFs Can Hurt Your Mood

1. Chronic Inflammation

   Higher UPF intake corresponds with elevated markers of inflammation, which are linked to depressive symptoms.

2. Gut-Brain Axis Disruption

   Dietary additives and low fibre in UPFs can alter gut microbiota and impair communication between your gut and brain, processes tied to mood regulation.

3. Additives that Affect the Brain

   Emulsifiers and certain artificial sweeteners have been shown in animal studies to trigger anxiety‑like behaviours and neuro-inflammation.

4. Blood‑Sugar Spikes & Crashes

   High sugar content in UPFs leads to rapid glucose swings, fuelling stress‑hormone imbalances and mood dips.

Practical Tips for Better Mood

1. Scan Ingredient Labels: Use the pom app to flag additives linked to inflammation, artificial sweeteners, and emulsifiers. Download on IOS or Android and start scanning for peace of mind.

2. Choose Whole Foods: Base your plate on fruits, veggies, whole grains, beans, nuts, eggs, and fresh meats.

3. Drink Smart: Replace sugary drinks with sparkling water infused with fresh fruit and herbs.

4. Prep Ahead: Batch cook healthy, delicious, and balanced dishes ahead of time to avoid grabbing convenience meals.

5. Snack Wisely: Go for plain yogurt plus berries or nuts instead of snack bars loaded with emulsifiers.