A large study of over 20,000 people looked at how diet quality and physical activity affect how long people live. The researchers found something interesting: for people without diabetes, eating a healthy diet was the most important factor for living longer. But for people with diabetes, getting enough exercise was more important than diet alone. The study tested four different healthy eating patterns and found that three of them worked well, especially when combined with exercise. These findings suggest that people with diabetes and those without might need different health strategies to live longer, healthier lives.

The Quick Take

  • What they studied: Whether eating healthy foods and exercising regularly help people live longer, and whether these benefits are different for people with diabetes versus those without diabetes
  • Who participated: Over 20,000 American adults from a national health survey, including people with diabetes and people without diabetes
  • Key finding: For people without diabetes, eating a high-quality diet reduced the risk of early death by 16-21%. For people with diabetes, regular physical activity reduced the risk of early death by about 2.7%. When people did both diet and exercise together, the benefits were even stronger for everyone.
  • What it means for you: If you have diabetes, focus on getting regular exercise as your top priority for living longer. If you don’t have diabetes, eating a healthy diet is especially important. Either way, doing both together is better than doing just one. Talk to your doctor about what’s best for your specific situation.

The Research Details

Researchers used information from a large national health survey that tracked American adults over many years. They looked at what people ate and how much they exercised, then followed them to see who stayed healthy and who passed away. They used a special statistical method called Cox regression to figure out the connection between diet, exercise, and living longer. The study examined four different types of healthy eating patterns: one that focuses on reducing inflammation in the body, one based on Mediterranean foods, one that emphasizes whole grains and vegetables, and one designed to lower blood pressure. They analyzed the data separately for people with diabetes and people without diabetes to see if the results were different.

This research approach is important because it looks at real people’s actual eating and exercise habits over time, rather than just testing one thing in a lab. By separating the results for people with and without diabetes, the study shows that different groups of people might need different health advice. This helps doctors and health experts give better recommendations tailored to each person’s situation.

This study is fairly reliable because it included a large number of people (over 20,000) and followed them for a long time. The researchers adjusted their analysis to account for other factors that might affect how long people live, like age, smoking, and income. However, the study is based on people’s memories of what they ate, which isn’t always perfectly accurate. Also, the study shows connections between diet/exercise and living longer, but it can’t prove that one directly causes the other.

What the Results Show

When people without diabetes ate a high-quality diet and exercised regularly, their risk of dying early dropped significantly. The Mediterranean diet and a healthy eating index both reduced mortality risk by about 16-21% when combined with exercise. For people with diabetes, the results were different: exercise was the strongest factor, reducing mortality risk by about 2.7%. Interestingly, diet quality alone didn’t show as much benefit for people with diabetes, but when combined with exercise, the benefits improved. One diet pattern called DASH (designed to lower blood pressure) didn’t show clear benefits for either group in this study.

The study found that combining diet and exercise was always better than doing either one alone, for both groups. A diet that reduces inflammation in the body showed promise for both people with and without diabetes. The benefits were strongest when people followed these healthy patterns consistently over time. The researchers calculated that if more people followed these recommendations, it could prevent a significant number of deaths in the population.

This study builds on previous research showing that both diet and exercise are important for health. However, it adds new information by showing that people with diabetes might benefit more from focusing on exercise, while people without diabetes see stronger benefits from diet. This suggests that diabetes changes how the body responds to different health behaviors, which is an important finding for personalizing health recommendations.

The study relied on people remembering what they ate, which can be inaccurate. The researchers couldn’t prove that diet and exercise directly caused people to live longer—only that they were connected. The study included mostly American adults, so the results might not apply to other countries or populations. Some of the results for people with diabetes were based on smaller numbers of people, making those findings less certain. The study couldn’t account for all the factors that might affect how long someone lives, like genetics or access to healthcare.

The Bottom Line

For people without diabetes: Focus on eating a high-quality diet based on Mediterranean foods or whole grains and vegetables. Add regular exercise for even better results. For people with diabetes: Make regular physical activity your priority, aiming for at least 150 minutes per week of moderate exercise. Also eat a healthy diet to maximize benefits. For everyone: Combining good eating habits with regular exercise is more effective than doing either one alone. These recommendations have moderate to strong evidence supporting them.

Everyone should care about these findings, especially people with diabetes who want to live longer and healthier lives. People without diabetes can use this information to prevent chronic diseases. Healthcare providers should use these findings to give personalized advice based on whether their patients have diabetes. People at risk for diabetes should pay special attention to diet quality. This research is less relevant for people with severe health conditions that prevent exercise—they should talk to their doctor about what’s safe for them.

You probably won’t notice dramatic changes immediately, but research suggests that consistent healthy eating and exercise habits can reduce health risks within 3-6 months. Major improvements in longevity and disease prevention typically show up over years of consistent behavior. Start with small changes and build up gradually for the best long-term results.

Want to Apply This Research?

  • Log your daily meals using a food quality tracker that scores your diet based on whole grains, vegetables, and healthy fats. Also track exercise minutes daily, aiming for 150 minutes per week of moderate activity like brisk walking or cycling.
  • If you have diabetes, set a goal to add 30 minutes of walking or other moderate exercise most days of the week. If you don’t have diabetes, focus on swapping processed foods for Mediterranean-style meals (more vegetables, olive oil, fish) while maintaining regular exercise. Use the app to set weekly reminders and celebrate small wins.
  • Check your diet quality score weekly and your exercise minutes daily. Every month, review your overall patterns to see if you’re meeting your goals. Track how you feel—energy levels, mood, and sleep quality—as these often improve before major health changes show up in medical tests. Share your progress with your doctor at regular checkups.

This research shows connections between diet, exercise, and living longer, but cannot prove one directly causes the other. These findings are based on American adults and may not apply to everyone. If you have diabetes or any chronic health condition, talk to your doctor before making major changes to your diet or exercise routine. This information is not a substitute for medical advice from your healthcare provider. Always consult with your doctor or a registered dietitian before starting a new diet or exercise program, especially if you take medications or have other health conditions.