Researchers tested whether a healthy eating plan called the MIND diet could help older adults keep their thinking skills sharp. They studied 604 people aged 65-85 who were overweight or obese. Some people followed the MIND diet (which focuses on brain-healthy foods like vegetables, nuts, and fish), while others ate their normal diet. After tracking their brain function over time, scientists found that the MIND diet seemed to help people with more severe obesity maintain better thinking skills. This suggests that what we eat might be especially important for brain health in people carrying extra weight.

The Quick Take

  • What they studied: Whether the MIND diet (a combination of Mediterranean and DASH eating styles focused on brain health) could help older adults keep their thinking and memory skills strong
  • Who participated: 604 adults between ages 65-85 who were overweight or obese. About two-thirds were women, and on average they were 70 years old with a body mass index of about 34
  • Key finding: The MIND diet appeared to help maintain brain function in people with a BMI of 35 or higher (more severe obesity), showing about 0.040 standardized units of improvement per year in thinking skills compared to those eating normally
  • What it means for you: If you’re an older adult with significant weight to lose, switching to a MIND diet rich in vegetables, berries, nuts, fish, and whole grains may help protect your thinking skills. However, this benefit wasn’t seen in people with lower BMI levels, so results may vary based on your individual situation

The Research Details

This was a randomized controlled trial, which is considered one of the strongest types of scientific studies. Researchers randomly assigned 604 older adults to either follow the MIND diet or continue eating their normal diet. The MIND diet emphasizes brain-healthy foods like leafy greens, berries, nuts, fish, olive oil, and whole grains while limiting red meat, butter, and processed foods.

Participants completed detailed brain function tests at the start of the study and then regularly throughout the study period. These tests measured 12 different thinking skills including memory, attention, and processing speed. Researchers then looked at whether certain characteristics of the participants—like their weight, age, genetics, exercise habits, and heart health—changed how well the MIND diet worked for protecting brain function.

The scientists used advanced statistical methods to separate out which factors truly made a difference in how the diet affected brain health, accounting for other variables that might influence thinking skills.

Understanding who benefits most from the MIND diet is important because it helps doctors and nutritionists give better personalized advice. Rather than recommending the same diet to everyone, knowing that people with obesity may see bigger brain benefits helps target interventions where they’re most likely to help. This approach to studying ’effect modifiers’ is valuable because real people are different, and treatments don’t work the same way for everyone.

This study has several strengths: it randomly assigned people to groups (reducing bias), included a substantial number of participants (604), and used objective brain function tests rather than relying on people’s memories. The researchers also carefully controlled for many other factors that could affect brain health. However, the study focused only on overweight and obese older adults, so results may not apply to people of normal weight or younger individuals. The study period and specific cognitive improvements were relatively modest in size.

What the Results Show

The main finding was that body mass index (BMI) was the only participant characteristic that significantly changed how well the MIND diet worked for brain health. Among people with a BMI of 35 or higher (indicating more severe obesity), those following the MIND diet showed better maintenance of thinking skills compared to those eating normally—about 0.040 standardized units of improvement per year.

To put this in perspective, this means that over a 5-year period, people with severe obesity on the MIND diet might maintain their cognitive abilities better than those not following the diet. However, this benefit was not seen in people with lower BMI levels, suggesting the diet’s protective effects may be strongest for those carrying the most extra weight.

Interestingly, other factors that researchers thought might matter—like age, sex, genetics (APOE gene status), exercise levels, and heart health markers—did not significantly change how the MIND diet affected brain function. This was somewhat surprising and suggests that BMI may be a particularly important factor in determining who benefits from this dietary approach.

The study examined several other potential factors that might influence the MIND diet’s effectiveness, including the APOE ε4 gene (which is associated with Alzheimer’s disease risk), physical activity levels, cardiovascular risk factors like blood pressure and cholesterol, and demographic factors like age and sex. None of these factors significantly modified the diet’s effect on brain health in this study population. This suggests that the MIND diet’s benefits for brain function may work through mechanisms related to weight management rather than through these other pathways.

Previous research has shown that the MIND diet can support brain health in older adults, but this study adds important new information by identifying that the benefits may be strongest for people with obesity. Earlier studies didn’t always look carefully at whether the diet worked differently for different groups of people. This finding aligns with growing evidence that obesity itself is a risk factor for cognitive decline, and that dietary interventions may be particularly valuable for addressing this risk in heavier individuals.

Several limitations should be considered when interpreting these results. First, the study only included people who were already overweight or obese, so we don’t know if these findings apply to people of normal weight. Second, the study measured thinking skills using standardized tests, which may not capture all aspects of real-world brain function. Third, the improvement in brain function, while statistically significant, was relatively small in practical terms. Fourth, the study didn’t track whether people actually stuck to the MIND diet long-term, which could affect real-world results. Finally, the study population was mostly female (65.5%) and relatively well-educated, so results may differ in other demographic groups.

The Bottom Line

If you are an older adult (65+) with a BMI of 35 or higher, adopting a MIND diet may help protect your thinking and memory skills. This diet emphasizes leafy greens, berries, nuts, fish, whole grains, and olive oil while limiting red meat, butter, and processed foods. This recommendation has moderate confidence based on this study, though more research is needed. For people with lower BMI levels, the evidence for cognitive benefits from the MIND diet is less clear from this particular study.

This research is most relevant for older adults (especially those 65+) who are overweight or obese and concerned about maintaining their thinking skills. It may also interest family members, caregivers, and healthcare providers working with this population. People of normal weight or younger individuals should not assume these findings apply to them, as the study was specific to older adults with obesity. Anyone with existing cognitive concerns or medical conditions should discuss dietary changes with their doctor.

Based on this study, improvements in brain function maintenance may take several months to become apparent, with more noticeable benefits likely over 1-2 years of consistent diet adherence. Brain health changes typically happen gradually, so patience and consistency are important. Some people may notice improvements in focus or memory sooner, while others may take longer to experience benefits.

Want to Apply This Research?

  • Track weekly servings of MIND diet foods: leafy greens (goal: 6+ servings), berries (goal: 2+ servings), nuts (goal: 5+ servings), fish (goal: 1+ servings), whole grains (goal: 3+ servings), and olive oil use. Also monitor weekly cognitive check-ins using simple memory or attention tasks
  • Start by adding one MIND diet food category per week: Week 1 add leafy greens to meals, Week 2 add berries as snacks, Week 3 add nuts, and so on. Use the app to log these additions and set reminders for shopping and meal prep. Create a weekly meal plan feature that suggests MIND diet recipes
  • Monthly cognitive self-assessments using simple tests (word recall, processing speed games), combined with adherence tracking to the MIND diet components. Set quarterly check-ins to review progress and adjust goals. Track weight changes alongside cognitive improvements to monitor the relationship between BMI reduction and brain health

This research suggests the MIND diet may help maintain thinking skills in older adults with obesity, but it is not a guarantee or cure for cognitive decline or dementia. Individual results vary based on genetics, overall health, lifestyle, and other factors. Before making significant dietary changes, especially if you have existing health conditions, take medications, or have concerns about your cognitive health, consult with your doctor or a registered dietitian. This information is for educational purposes and should not replace professional medical advice. If you experience memory problems or cognitive changes, seek evaluation from a healthcare provider.