Ultra-Processed Foods and Mental Health: What the Research Actually Says

TLDR: Ultra-Processed Foods and Mental Health—The Science Is Clear

This article examines the growing body of research linking consumption of ultra-processed foods to mental health outcomes, with implications for both individual well-being and public policy. Key points include:

1. Meta-analyses show ultra-processed food consumption is associated with a 53% higher risk of common mental disorder symptoms

2. For every 10% increase in ultra-processed food intake relative to daily calories, there's an 11% higher risk of depression

3. Multiple biological mechanisms explain these associations, including inflammation, gut-brain axis disruption, and nutrient displacement

4. The US is finally beginning to address ultra-processed foods at the policy level, though we lag behind other countries

5. Individual change matters, but systemic change is essential—this isn't about personal failure

Wise Mind Nutrition emphasizes the importance of:

• Understanding that food quality affects mental health through multiple biological pathways

• Approaching dietary change with compassion and awareness, not shame or restriction

• Recognizing the role of food systems in shaping what we eat—being hard on systems while soft on people

• Using trauma-informed, eating disorder-aware approaches when making any dietary modifications

• Advocating for policy changes while also supporting personal agency

[Read the full article to learn how to understand the public health implications of ultra-processed foods]

The Conversation Is Finally Happening

The Food You Eat Is Shaping Your Brain—And Policy Makers Are Finally Starting to Notice.

Something shifted in 2025. After years of researchers like Carlos Monteiro and the NOVA classification system raising awareness of the issue of ultra-processed foods, the US government has finally begun to pay attention. In July 2025, the FDA and USDA issued a joint Request for Information seeking to develop a uniform definition of ultra-processed foods—a critical first step toward meaningful policy [1].

This isn't happening in a vacuum. The research linking ultra-processed foods to poor mental health outcomes has reached a point where it can no longer be ignored. And as someone who works with people struggling with depression, anxiety, ADHD, PTSD, substance use disorders, and eating disorders, I can tell you this conversation matters deeply.

But here's what I want to be clear about from the start: this isn't about food shaming. This isn't about making anyone feel bad about what they've eaten. The rise of ultra-processed foods in our diets is a systemic issue driven by food corporations, agricultural policy, and economic forces far beyond individual choice. We need to be hard on systems while being soft on people.

What the Research Actually Shows

Let's start with the numbers, because they're striking.

A systematic review and meta-analysis examining 17 observational studies with over 385,000 participants found that greater ultra-processed food consumption was associated with a 53% higher odds of experiencing depressive and anxiety symptoms combined [2]. When researchers looked at depression specifically, the odds ratio was 1.44—meaning those who consumed more ultra-processed foods had 44% higher odds of depressive symptoms compared to those who consumed less.

The dose-response relationship is particularly compelling. For every 10% increase in ultra-processed food consumption relative to daily caloric intake, there's an 11% higher risk of depression [3]. This isn't a vague association—it's a measurable, proportional relationship.

Perhaps the most rigorous evidence comes from the Nurses' Health Study II, which followed over 31,000 women for up to 14 years. Those in the top fifth of ultra-processed food consumers—eating nine or more servings per day—had a 50% higher risk of developing depression than those in the bottom fifth, eating four or fewer servings daily [4]. This was after controlling for exercise, smoking, and other confounding factors.

The connection extends to anxiety as well. Cross-sectional studies show that high ultra-processed food intake is associated with 48% higher odds of anxiety symptoms [2]. In adolescents, higher consumption of ultra-processed foods correlates with boredom, crying, fear, worry, loneliness, and unhappiness [5].

Why This Happens: The Biological Mechanisms

The association between ultra-processed foods and mental health isn't mysterious—we have a reasonably good understanding of the biological pathways involved.

Inflammation is central. Ultra-processed foods promote inflammatory responses through multiple mechanisms: emulsifiers that disrupt gut barrier function, high glycemic loads that trigger metabolic stress, and low fiber content that starves beneficial gut bacteria [6]. Chronic systemic inflammation is now recognized as a key feature of depression, affecting up to 27% of patients with major depressive disorder [7].

The gut-brain axis takes a hit. Ultra-processed foods compromise the gut microbial ecosystem, reducing diversity and promoting dysbiosis [8]. This matters because the gut produces approximately 95% of the body's serotonin and communicates directly with the brain through the vagus nerve.

Nutrient displacement compounds the problem. Ultra-processed foods tend to be energy-dense but nutrient-poor. When they dominate the diet, they displace foods that provide the building blocks for neurotransmitter synthesis and neural function, such as omega-3 fatty acids, B vitamins, zinc, magnesium, and polyphenols [9].

The brain's reward system gets hijacked. Ultra-processed foods are engineered for hyper-palatability—combinations of sugar, salt, fat, and texture that override normal satiety signals and drive overconsumption [10]. This isn't about willpower; it's about neurochemistry.

The tryptophan diversion pathway. Here's something that doesn't get enough attention: tryptophan can become serotonin, but it can also become kynurenine, which can then become quinolinic acid—a neurotoxic compound [11]. In inflammatory environments, more tryptophan is diverted to the kynurenine pathway than to serotonin synthesis. This is why simply supplementing with tryptophan doesn't reliably improve depression—it's not just what you take, but the environment in which you take it (the “terrain” as we call it in functional medicine).

The Policy Landscape: Where the US Stands

Here's where it gets interesting. The US has historically lagged far behind other countries in addressing ultra-processed foods through policy. But that's beginning to change.

In July 2025, the FDA and USDA jointly requested information to help establish a uniform definition of ultra-processed foods for the US food supply [1]. This might seem like a small step, but it's actually significant—you can't regulate what you can't define.

Compare this to what other countries have already accomplished:

Brazil became the first country to recommend reducing consumption of ultra-processed foods in its national dietary guidelines in 2014 [13]. The country's national school feeding program now requires that 90% of meals be unprocessed or minimally processed foods.

Chile implemented comprehensive food labeling laws requiring black octagonal warning labels on foods high in calories, sugars, fats, or sodium [15]. They banned marketing of these products to children under 14 and restricted their sale in school settings.

Colombia implemented an excise tax on ultra-processed foods that increased from 10% in 2023 to 20% in November 2025 [16].

Norway recently passed legislation banning the marketing of unhealthy foods to children under 18 [17].

The US has been notably absent from this list—until now. Whether the current policy momentum translates into meaningful change remains to be seen.

What This Means for You

If you're reading this on the Wise Mind Nutrition website, you're probably already thinking about the relationship between what you eat and how you feel. So let me offer some nuanced thoughts.

This isn't about perfection or restriction. If you have a history of eating disorders, trauma, or disordered eating, the last thing you need is another reason to feel anxious about food. The research on ultra-processed foods is important, but it doesn't override your need for psychological safety around eating.

Context matters enormously. For someone in eating disorder recovery who has been severely restricting, a packaged snack might be precisely what they need to challenge fear foods. For someone with binge-type eating patterns who clearly meets criteria for ultra-processed food addiction, the same snack might be a trigger. There's no universal recommendation here.

Start with curiosity, not judgment. If you suspect ultra-processed foods might be affecting your mental health, approach the question with openness. Notice how you feel after different meals. Gather data about your own experience rather than following rigid rules.

Address the underlying drivers. Ultra-processed foods are often appealing because they're convenient, affordable, and engineered to taste good. If you're eating them because you're exhausted, stressed, time-poor, or seeking comfort, addressing those underlying issues matters more than the food itself.

The Bigger Picture

I want to end where I started: with the systemic nature of this issue.

Ultra-processed foods now account for approximately 57% of calories consumed in the US, and this proportion is even higher among children and adolescents [18]. This didn't happen because millions of people simultaneously made bad choices. It happened because of agricultural subsidies, food science engineering, marketing budgets that dwarf public health campaigns, and economic pressures that make convenience foods the only practical option for many families.

At the individual level, we can make choices that support our mental health. At the community level, we can advocate for healthier food environments. At the policy level, we can push for comprehensive approaches like those implemented by other countries.

But we do this without shame. Without blame. Without moralizing about food choices. We recognize that the food system has been designed to sell products, not optimize health, and we work to change that system while extending compassion to ourselves and others who are navigating it.

This is what it means to be hard on systems while soft on people.

References

1. FDA. Ultra-processed foods. FDA.gov. 2025.

2. Lane MM, Gamage E, Du S, et al. Ultra-processed food consumption and mental health: A systematic review and meta-analysis. Nutrients. 2022;14(13):2568.

3. Mazloomi SN, et al. The association of ultra-processed food consumption with depression: A systematic review and dose-response meta-analysis. Eur J Nutr. 2022;61:2485-2498.

4. Samuthpongtorn C, et al. Consumption of ultraprocessed food and risk of depression. JAMA Netw Open. 2023;6(9):e2334770.

5. Monteiro CA, et al. Ultra-processed foods and human health: The main thesis and the evidence. Lancet. 2025.

6. Lane MM, et al. Ultra-processed food exposure and adverse health outcomes: Umbrella review of epidemiological meta-analyses. BMJ. 2024;384:e077310.

7. Osimo EF, et al. Inflammatory markers in depression: A meta-analysis. Brain Behav Immun. 2020;87:901-909.

8. Cuevas-Sierra A, et al. Gut microbiota differences according to ultra-processed food consumption. Nutrients. 2021;13(8):2710.

9. Sarris J, et al. Clinician guidelines for treatment of psychiatric disorders with nutraceuticals. World J Biol Psychiatry. 2022;23(6):424-455.

10. Hall KD, et al. Ultra-processed diets cause excess calorie intake and weight gain. Cell Metab. 2019;30(1):67-77.

11. Savitz J. The kynurenine pathway: A finger in every pie. Mol Psychiatry. 2020;25(1):131-147.

12. FDA. Human Food Program (HFP) FY 2025 priority deliverables. FDA.gov. 2025.

13. Monteiro CA, et al. Dietary guidelines to nourish humanity and the planet: A blueprint from Brazil. Public Health Nutr. 2015;18(13):2311-2322.

14. Scrinis G, et al. Policies to halt and reverse the rise in ultra-processed food production. Lancet. 2025.

15. Taillie LS, et al. An evaluation of Chile's Law of Food Labeling and Advertising. PLoS Med. 2020;17(2):e1003015.

16. Daniels JP. Colombia introduces junk food tax. Lancet. 2023;402(10417):2062.

17. Norwegian Government. Forskrift om forbud mot markedsføring av næringsmidler rettet mot barn. Lovdata. 2025.

18. Wang L, et al. Trends in consumption of ultraprocessed foods among US youths. JAMA. 2021;326(6):519-530.

19. Scrinis G, et al. Policies to halt and reverse the rise in ultra-processed food production, marketing, and consumption. Lancet. 2025.