Research shows that adults eating the most fast food, sugary drinks, and fried foods have more than double the risk of depression symptoms compared to those eating the least, according to a 2026 Gram Research analysis of nearly 7,000 Dutch adults followed over several years. The effect was particularly strong in smokers. Conversely, diets rich in vegetables and legumes appeared protective, though the benefit was less dramatic. While this doesn’t prove food causes depression, it suggests dietary changes could help reduce mental health risk.
A major study of nearly 7,000 adults found that people who eat a lot of fast food, sugary drinks, and fried foods have a significantly higher risk of developing depression and anxiety symptoms. Researchers from the Maastricht Study tracked what people ate and monitored their mental health over time, discovering that a diet heavy in processed foods increased depression risk by more than double compared to healthier eating patterns. Meanwhile, diets rich in vegetables and legumes appeared protective. According to Gram Research analysis, this long-term study provides strong evidence that what we eat directly impacts our mental health, suggesting that dietary changes could be an important tool for preventing mood and anxiety disorders.
Key Statistics
A 2026 cohort study of 6,967 adults published in the American Journal of Clinical Nutrition found that those with the highest adherence to a ‘high fast food and sugar’ dietary pattern had a 113% increased risk of depression symptoms compared to those with the lowest adherence.
In smokers specifically, adherence to a high fast food and sugar diet was associated with a 62% increased risk of depression symptoms, according to the Maastricht Cohort Study of nearly 7,000 adults.
A diet high in vegetables and legumes showed a protective trend against depression in a 2026 analysis of 6,967 adults, though the effect was not statistically significant in the overall population.
The Quick Take
- What they studied: Whether eating patterns—specifically diets high in junk food versus diets high in vegetables—affect a person’s chances of developing depression or anxiety
- Who participated: Nearly 7,000 Dutch adults with an average age of 60 years old, about half men and half women, who answered detailed questions about their eating habits and took mental health surveys every year
- Key finding: Adults who ate the most fast food, sugary drinks, and fried foods had more than twice the risk of depression symptoms compared to those who ate the least of these foods. The effect was particularly strong in smokers.
- What it means for you: Eating fewer processed foods and more vegetables might help protect your mental health. However, this doesn’t mean food alone causes depression—many factors matter, including genetics, stress, and sleep. Talk to a doctor if you’re experiencing depression or anxiety symptoms.
The Research Details
This was a cohort study, which means researchers followed the same group of people over time rather than just taking a snapshot. Participants filled out a detailed food questionnaire asking what they ate, and researchers used a statistical method called principal component analysis to identify three main eating patterns: one heavy in vegetables and legumes, one heavy in fast food and sugar, and one vegetarian-style diet. Each year for several years, participants completed mental health questionnaires designed to detect depression and anxiety symptoms. Researchers then used statistical tools to see which eating patterns were connected to higher or lower rates of depression and anxiety.
The strength of this approach is that it followed real people in their daily lives over time, rather than just asking them to remember their eating habits from years ago. Researchers also adjusted their analysis for many other factors that could affect mental health, like smoking, exercise, body weight, and diabetes status. This helps isolate the effect of diet itself.
Following people over time (rather than just surveying them once) gives us much stronger evidence about cause and effect. This study design is considered more reliable than simple surveys because it shows what actually happens to people’s mental health when they eat certain foods. By measuring mental health regularly with validated questionnaires, researchers could catch depression and anxiety symptoms early, not just severe cases.
This study was published in a highly respected nutrition journal and included a large, diverse group of adults. The researchers carefully controlled for many confounding factors (things that could muddy the results, like smoking or weight). However, this was still an observational study—people chose their own diets, so we can’t be 100% certain that the food caused the mental health changes rather than other lifestyle factors. The study was also conducted in the Netherlands, so results may not apply equally to all populations worldwide.
What the Results Show
The most striking finding was about the “high fast food and sugar” diet pattern. Adults who followed this pattern most closely had a 113% higher risk of depression symptoms—meaning more than double the risk—compared to those who followed it least. This association remained strong even after accounting for other factors like age, sex, smoking, exercise, and body weight. The effect was even stronger in people who smoked, where the risk increased by 62% for current or former smokers.
Interestingly, the “high vegetables and legumes” diet pattern showed a protective effect, though the results were less dramatic. People who ate more vegetables and legumes had a lower risk of depression, though this finding was not statistically significant in the full group.
For anxiety disorder specifically, the results were less clear. While the high fast food and sugar pattern showed a trend toward increased anxiety risk, the relationship was weaker and not statistically significant in the overall group. However, in smokers, there was a suggestion of increased anxiety risk with the junk food diet.
The vegetarian-like diet pattern (high in vegetables, legumes, and whole grains) showed no significant association with either depression or anxiety in the main analysis.
When researchers looked at specific subgroups, interesting patterns emerged. The connection between junk food and depression was particularly strong in smokers and in people without diabetes. In people with diabetes, the relationship was weaker, possibly because they were already making more conscious dietary choices. The effect also appeared somewhat stronger in women than men, though this difference wasn’t dramatic. These subgroup findings suggest that diet’s impact on mental health may depend on other lifestyle factors and health conditions.
Previous research on diet and mental health has been mixed and often relied on one-time surveys rather than following people over time. This study is stronger because it tracked the same people repeatedly and used more rigorous statistical methods. The finding that ultra-processed foods are linked to depression aligns with several smaller studies, but this is one of the largest and longest studies to examine this question. The protective effect of vegetables and legumes is also consistent with previous research, though the effect size here was smaller than some earlier studies suggested.
This study followed Dutch adults, so results may not apply equally to people in other countries with different food cultures or genetic backgrounds. Participants were also relatively older (average age 60) and generally healthier than the general population, so findings may not apply to younger people or those with serious health conditions. While researchers adjusted for many factors, they couldn’t account for everything—for example, stress levels, sleep quality, and social relationships also affect mental health but weren’t measured. Finally, because people chose their own diets, we can’t prove that the food caused the mental health problems; it’s possible that people with depression symptoms changed their eating habits, rather than the food causing the depression.
The Bottom Line
Reduce consumption of fast food, sugary drinks, fried foods, and refined grains. Increase intake of vegetables, legumes, and whole grains. These dietary changes may help reduce depression and anxiety risk, though diet is just one piece of mental health—sleep, exercise, social connection, and stress management matter too. Confidence level: Moderate for depression (strong evidence), Lower for anxiety (weaker evidence in this study).
Anyone concerned about depression or anxiety prevention should pay attention to this research. It’s especially relevant for people with risk factors like smoking or a family history of depression. People already experiencing depression or anxiety should not view diet as a replacement for professional mental health treatment, but rather as a complementary approach. Discuss dietary changes with your doctor or a mental health professional.
Mental health changes from dietary improvements typically take weeks to months to become noticeable. Don’t expect immediate mood changes from eating better, but consistent dietary improvements over 2-3 months may contribute to better mental health alongside other healthy habits.
Frequently Asked Questions
Can eating better help with depression and anxiety?
Research suggests dietary changes may help reduce depression and anxiety risk. A 2026 study of nearly 7,000 adults found those eating the most fast food had double the depression risk. However, diet alone isn’t a treatment—combine it with professional help, exercise, and sleep for best results.
What foods should I avoid if I’m worried about depression?
Limit fast food, sugary drinks, fried foods, refined grains, and processed snacks. A 2026 study found these foods were linked to significantly higher depression risk. Instead, focus on vegetables, legumes, whole grains, and minimally processed foods.
How long does it take for diet changes to improve mental health?
Mental health improvements from dietary changes typically take 2-3 months to become noticeable. Consistency matters more than perfection. Track your mood weekly while making gradual dietary improvements to see if you notice patterns.
Does this mean food causes depression?
Not necessarily. This study shows an association—people eating junk food have higher depression rates—but doesn’t prove food causes it. Many factors affect mental health: genetics, stress, sleep, relationships, and exercise all matter. Diet is one piece of a larger puzzle.
Should I stop eating all processed foods?
The study focused on patterns, not individual foods. Aim to reduce fast food, sugary drinks, and fried foods while increasing vegetables and legumes. Small, sustainable changes work better than eliminating entire food groups. Work with a nutritionist for personalized guidance.
Want to Apply This Research?
- Log daily servings of vegetables, legumes, and whole grains versus fast food and sugary drinks. Track mood and anxiety levels weekly using a simple 1-10 scale to correlate dietary patterns with mental health over time.
- Set a specific goal like “replace one fast food meal per week with a home-cooked meal containing vegetables and legumes” or “swap sugary drinks for water or unsweetened beverages.” Use the app to plan meals and track progress toward these goals.
- Create a dashboard showing weekly averages of healthy versus processed food intake alongside weekly mood/anxiety scores. Look for patterns over 4-8 weeks to see if dietary improvements correlate with mental health improvements. Share results with a healthcare provider for personalized guidance.
This research shows an association between dietary patterns and depression/anxiety risk, but does not prove that diet alone causes these conditions. Depression and anxiety are complex disorders with multiple causes including genetics, stress, sleep, exercise, and social factors. This information should not replace professional mental health treatment. If you are experiencing depression or anxiety symptoms, consult a healthcare provider or mental health professional. Dietary changes should complement, not substitute for, professional mental health care. Individual results may vary based on genetics, overall lifestyle, and other health conditions.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.