Researchers wanted to know if eating a vegan diet (no animal products) or a regular diet (with meat and dairy) affects stress levels and mental wellbeing differently. They studied 159 African American adults for 2 years, with some people eating vegan and others eating regular diets. Both groups felt less stressed over time, and both groups felt better mentally by the end. Surprisingly, the type of diet didn’t matter—people improved their mental health about the same way whether they ate vegan or regular food. This challenges the idea that one diet is clearly better for your mood and stress levels.

The Quick Take

  • What they studied: Does eating a vegan diet (no meat, dairy, or eggs) help reduce stress and improve mood better than eating a regular diet that includes animal products?
  • Who participated: 159 African American adults between 18 and 65 years old who were overweight or had obesity. Half were randomly assigned to eat vegan, and half continued eating regular diets.
  • Key finding: Both groups experienced lower stress levels and better mental wellbeing over 2 years, with no meaningful difference between the vegan and regular diet groups. This means the diet type itself wasn’t what made the difference—something else about the study helped both groups feel better.
  • What it means for you: If you’re thinking about changing your diet to feel less stressed or happier, the good news is that making any positive dietary change may help. You don’t necessarily need to go vegan to improve your mental health. However, this study only looked at African American adults, so results may differ for other groups.

The Research Details

This was a randomized controlled trial, which is one of the strongest types of research studies. Researchers randomly assigned 159 people to either follow a vegan diet or continue eating a regular diet for 2 years. Random assignment is important because it helps ensure the two groups are similar at the start, so any differences in results are more likely due to the diet itself rather than other factors.

The researchers measured stress and mental wellbeing at the beginning of the study and then again at 6 months, 12 months, and 24 months. They used standard questionnaires that ask people about their stress levels and how they feel mentally. They analyzed the results using a method called “intent-to-treat,” which means they included everyone who started the study in the final results, even if some people didn’t stick with their assigned diet perfectly.

This study is particularly valuable because most previous research on vegan diets and mental health included mostly white participants. This study focused on African American adults, which helps fill an important gap in nutrition research.

Using a randomized controlled trial design is important because it’s much stronger evidence than simply comparing people who already chose to be vegan versus those who didn’t. When people choose their own diet, other factors (like personality or life circumstances) might affect their mental health, making it hard to know if the diet itself made the difference. By randomly assigning people, researchers can be more confident that changes in stress and mood are actually related to the diet change.

This study has several strengths: it followed people for 2 years (a long time), it used random assignment, and it included a diverse population that’s often underrepresented in nutrition research. However, the study only included African American adults, so we can’t be sure the results apply to other racial or ethnic groups. Also, some people may have dropped out or not followed their assigned diet perfectly, which could affect the results.

What the Results Show

Both the vegan group and the regular diet group experienced decreased stress over the 2-year study period. The regular diet group showed improvements in stress at 6, 12, and 24 months. The vegan group showed improvements at 12 and 24 months (though the 6-month measurement wasn’t as clear).

For mental wellbeing, the regular diet group showed clear improvement at 24 months. The vegan group also improved, but the improvement wasn’t as pronounced at the final measurement.

The most important finding was that there were no statistically significant differences between the two groups at any point during the study. This means that whether someone ate vegan or regular food, their stress reduction and mental wellbeing improvements were essentially the same. The researchers also looked specifically at people who stuck closely to their assigned diet, and even among these committed participants, there were no differences between groups.

The study found that simply participating in a structured nutrition program—regardless of which diet type—appeared to benefit mental health. Both groups received nutrition education, support, and monitoring, which may have contributed to the improvements seen in both groups. This suggests that the act of making a deliberate dietary change and receiving support might be just as important as the specific type of diet chosen.

Previous research on vegan diets and mental health has shown mixed results. Some studies suggested that vegan diets reduce stress and improve mood, while others found the opposite or found no difference. This NEW Soul study adds important evidence by showing no difference between vegan and omnivorous diets in a diverse population. It suggests that earlier conflicting results might have been due to differences in study design, population, or other factors rather than the diet itself being superior.

This study only included African American adults, so we don’t know if the same results would apply to people of other racial or ethnic backgrounds. Some participants may have dropped out or not followed their assigned diet perfectly, which could affect the results. The study measured stress and mental wellbeing using questionnaires, which rely on people’s own reports rather than biological measurements. Additionally, both groups received nutrition education and support, which might have helped both groups equally, making it harder to see differences between the diets themselves.

The Bottom Line

If you’re interested in improving your mental health through diet, the evidence suggests that making a positive dietary change—whether vegan or omnivorous—may help reduce stress and improve wellbeing. The key appears to be making a deliberate change and sticking with it, rather than choosing a specific diet type. Consider working with a healthcare provider or registered dietitian to find an eating pattern that works for you and that you can maintain long-term. (Moderate confidence level—this is one study in one population)

This research is most relevant to African American adults who are overweight or have obesity and are interested in how diet affects their mental health. However, the general principle that dietary changes may support mental wellbeing could apply more broadly. People considering a vegan diet specifically for mental health benefits should know that a regular diet with animal products may work just as well. Anyone with diagnosed mental health conditions should continue working with their healthcare provider rather than relying solely on diet changes.

In this study, improvements in stress and mental wellbeing took time to develop. The regular diet group showed stress improvements as early as 6 months, while the vegan group showed clearer improvements by 12 months. Mental wellbeing improvements were most noticeable at 24 months (2 years). If you make dietary changes, expect to give yourself at least several months to notice mental health benefits, and ideally track changes over a year or more.

Want to Apply This Research?

  • Track your perceived stress level weekly using a simple 1-10 scale and your overall mood/wellbeing using the same scale. Record these alongside your dietary adherence (percentage of days you followed your chosen eating pattern). This allows you to see if your mental health improves as you maintain consistent dietary changes over weeks and months.
  • Set a specific dietary goal (whether vegan or omnivorous) and commit to it for at least 3 months. Use the app to log your meals, receive nutrition education reminders, and track your progress. The research suggests that the structure and support of a nutrition program itself may be beneficial, so use app features like goal-setting, reminders, and progress tracking to maintain consistency.
  • Create a long-term tracking dashboard that shows your stress and wellbeing trends over 6, 12, and 24 months alongside your dietary consistency. Include monthly check-ins where you reflect on how you’re feeling mentally and physically. This mirrors the study’s approach and helps you identify patterns between your eating habits and mental health over meaningful time periods.

This research suggests that both vegan and omnivorous diets may support mental health improvements, but it does not replace professional mental health treatment. If you are experiencing depression, anxiety, or other mental health concerns, please consult with a healthcare provider or mental health professional. This study was conducted in African American adults with overweight or obesity, so results may not apply to all populations. Before making significant dietary changes, especially if you have existing health conditions or take medications, consult with your doctor or a registered dietitian. This summary is for educational purposes and should not be considered medical advice.