A new review of 11 studies involving over 3,400 people found that combining healthy eating with regular exercise may help protect and improve brain function better than doing just one or the other. The research showed improvements in memory, thinking speed, and decision-making skills. The benefits were especially strong for people who were already showing signs of memory problems. While the combination approach worked well, the study found that doing diet and exercise together didn’t dramatically outperform doing them separately when it comes to overall brain function—but the combination still helped.

The Quick Take

  • What they studied: Whether combining a healthy diet with exercise helps brain function more than doing just diet changes or just exercise alone
  • Who participated: 3,428 people across 11 different research studies. Some participants were healthy, while others had early signs of memory problems or were at risk for cognitive decline
  • Key finding: The combination of diet and exercise improved overall thinking ability, memory, and decision-making skills. The improvement was moderate in size and most noticeable in people who already had some memory concerns
  • What it means for you: If you’re concerned about keeping your brain sharp as you age, doing both healthy eating and regular exercise together appears to be a smart approach. However, doing one or the other is still beneficial—the combination just seems to work a bit better, especially if you’re already noticing memory changes

The Research Details

Researchers searched four major scientific databases for studies that tested whether combining diet and exercise improved brain function. They only included high-quality studies where people were randomly assigned to different groups—some doing diet changes, some exercising, some doing both, and some doing neither. This type of study design is considered very reliable because it reduces bias.

The researchers then combined the results from all 11 studies using a statistical method called meta-analysis. This approach is like pooling everyone’s results together to see the bigger picture. They used a technique that accounts for differences between studies, since not all studies are identical. They also rated the quality of the evidence using a standard system called GRADE to help readers understand how confident they should be in the results.

This research approach is important because individual studies sometimes give different answers. By combining multiple studies, researchers can see patterns that might not be obvious in just one study. The meta-analysis approach also helps determine whether benefits are real or just happened by chance. Using the GRADE system helps readers understand that while the results are promising, they’re based on moderate-quality evidence—meaning future research might refine these findings.

The studies included were randomized controlled trials, which is the gold standard in research. The combined evidence was rated as moderate quality, meaning the findings are fairly reliable but not perfect. Some variation existed between studies (shown by the I² values), which is normal. The fact that 3,428 people were studied across 11 different trials strengthens confidence in the results. However, readers should know that the studies used different types of diets and exercise programs, which could affect how well the results apply to everyone.

What the Results Show

The combined diet and exercise approach improved three main areas of brain function: overall thinking ability improved by about 32%, memory improved by about 29%, and decision-making skills (called executive function) improved by about 52%. These improvements were consistent across the studies examined.

Interestingly, when researchers compared the combined approach directly against doing diet alone or exercise alone, the differences weren’t as dramatic as expected. This suggests that both diet and exercise are individually powerful tools for brain health, and combining them provides additional but not revolutionary benefits.

The benefits were much stronger for people who already had memory concerns or were at risk for cognitive decline. In this group, the combined approach showed a 76% improvement in overall thinking ability. For people with normal brain function, the improvement was smaller at about 10%. This finding is important because it suggests the intervention works best as a preventive measure for those showing early warning signs.

The research identified which specific diets worked best: the DASH diet (Dietary Approaches to Stop Hypertension) showed particularly strong benefits, improving overall thinking by about 77%. Supervised dietary programs also showed benefits. For decision-making skills specifically, two types of brain tests showed improvement: the Stroop test (which measures how quickly you can switch between tasks) improved by 39%, and the Trail Making Test (which measures processing speed) improved by 63%.

Previous research has shown that both diet and exercise individually help protect brain health. This study confirms those findings and suggests that doing both together provides additional benefits. The finding that the combination isn’t dramatically better than single interventions aligns with some recent research suggesting that consistency and adherence to either approach may matter more than which specific approach you choose. This research adds nuance to the conversation by showing that while combination therapy helps, people shouldn’t feel discouraged if they can only commit to diet or exercise alone.

The studies used different types of diets and exercise programs, making it hard to say exactly which combinations work best. Some studies had small numbers of participants. The quality of evidence was rated as moderate, not high, meaning future research might change these conclusions. Most studies were relatively short-term, so we don’t know if benefits last for years. The studies didn’t always measure the same brain functions the same way, which required researchers to combine different types of measurements. Additionally, people who volunteer for lifestyle studies might be more motivated than the general population, so results might not apply equally to everyone.

The Bottom Line

If you’re concerned about brain health or memory: Try combining a healthy diet (especially the DASH diet) with regular exercise. Aim for at least 150 minutes of moderate exercise per week and focus on whole foods, vegetables, and lean proteins. This combination appears to be moderately effective (moderate confidence level). If you can only do one, either diet or exercise alone still provides real benefits—don’t let perfect be the enemy of good. If you’re already experiencing memory problems or are at high risk for cognitive decline, this combination approach is particularly worth trying (higher confidence level for this group).

This research is most relevant for: people over 50, anyone with a family history of memory problems, people with early signs of memory changes, and anyone wanting to maintain sharp thinking as they age. People with normal brain function can still benefit, but the improvements are more modest. Anyone with existing health conditions should talk to their doctor before starting a new diet or exercise program.

Most studies lasted between 6 months and 2 years. You might notice improvements in memory and thinking speed within 3-6 months of consistent diet and exercise changes, but the most significant benefits typically appear after 6-12 months. Brain health is a long-term investment—these changes work best when maintained over years, not weeks.

Want to Apply This Research?

  • Track two metrics weekly: (1) Exercise minutes completed (goal: 150 minutes moderate activity per week), and (2) DASH diet adherence score (daily checklist of servings of vegetables, fruits, whole grains, lean proteins, and low-fat dairy). Create a simple 0-10 rating of mental clarity and memory each week to monitor subjective improvements.
  • Set up a combined activity: schedule a 30-minute walk while listening to educational content, or meal prep healthy recipes on Sunday while planning the week’s exercise. This links diet and exercise together psychologically. Use app reminders for both diet logging and exercise scheduling at the same time each day to build the habit of doing them together.
  • Monthly: Review trends in exercise consistency and diet quality scores. Quarterly: Reassess subjective memory and thinking clarity using simple self-rating scales. Every 6 months: Consider formal cognitive testing if available through your healthcare provider to track objective improvements. Keep a simple journal of any noticed improvements in memory, focus, or mental energy.

This research summary is for educational purposes only and should not replace professional medical advice. The findings suggest that combined diet and exercise interventions may support brain health, but individual results vary. Before starting any new diet or exercise program, especially if you have existing health conditions, memory concerns, or take medications, consult with your healthcare provider. This research does not diagnose, treat, or cure any medical condition. If you’re experiencing significant memory problems or cognitive changes, seek evaluation from a qualified healthcare professional.