Researchers studied nearly 3,000 Iranian adults to see if eating foods that are good for both our bodies and the environment could help prevent metabolic syndrome—a group of health problems that affect about 1 in 3 people in Iran. They found that people who ate more sustainable, healthy foods had about half the risk of developing metabolic syndrome compared to those who ate less sustainably. This suggests that choosing foods that are better for the planet might also be better for your health.

The Quick Take

  • What they studied: Whether eating foods that are healthy and good for the environment helps prevent metabolic syndrome, which is a combination of health problems like high blood pressure, high blood sugar, and extra belly fat.
  • Who participated: 2,971 adults living in Iran, aged 35 to 70 years old, who were part of a larger health study called the PERSIAN Dena Cohort.
  • Key finding: Adults who ate the most sustainable and healthy foods had 48% lower chances of having metabolic syndrome compared to those who ate the least sustainably. This difference was statistically significant, meaning it’s unlikely to be due to chance.
  • What it means for you: Choosing foods that are both nutritious and environmentally friendly—like plant-based options and sustainably produced items—may help protect your heart and metabolic health. However, this study shows an association, not proof that diet changes will definitely prevent the condition.

The Research Details

This was a cross-sectional study, which means researchers looked at a large group of people at one point in time and compared their eating habits to their health status. The researchers asked 2,971 Iranian adults about what they ate using detailed food questionnaires, then calculated a special score called the WISH (World Index for Sustainability and Health) score based on 13 different food items. This score measures how well someone’s diet balances being good for their body and good for the environment. The researchers then checked who had metabolic syndrome using standard medical criteria and looked for connections between the WISH score and the condition.

This approach is important because it allowed researchers to study a large, real-world population and identify patterns between sustainable eating and health outcomes. By measuring both health and environmental factors in one score, the study shows that what’s good for the planet might also be good for people’s bodies. The cross-sectional design is efficient for finding associations, though it can’t prove that diet changes directly cause health improvements.

The study used validated questionnaires, meaning the tools for measuring diet have been tested and proven reliable. The researchers controlled for other factors that might affect results, like age and lifestyle. However, because this is a cross-sectional study, we can’t be completely certain about cause-and-effect relationships. The study was conducted in Iran, so results may not apply equally to all populations worldwide.

What the Results Show

The main finding was striking: people with the highest WISH scores (meaning they ate the most sustainable and healthy foods) had 48% lower odds of having metabolic syndrome compared to those with the lowest scores. This means if 100 people with low WISH scores had metabolic syndrome, only about 52 people with high WISH scores would be expected to have it. The relationship was consistent across different groups, with the risk decreasing as people’s WISH scores increased. This pattern held true even after researchers accounted for other factors like age, physical activity, and education that might influence the results.

The study also found that specific components of metabolic syndrome improved with higher WISH scores. People eating more sustainably had lower rates of belly fat (abdominal adiposity), better blood sugar control, and lower triglycerides (a type of fat in the blood). These improvements suggest that sustainable eating patterns benefit multiple aspects of metabolic health, not just one area.

Previous research has shown that various healthy eating patterns reduce metabolic syndrome risk, but this is one of the first studies to specifically examine sustainable diets in this context. The findings align with research showing that plant-forward diets are beneficial for health, and they add the important dimension of environmental sustainability. This bridges nutrition science with environmental health, suggesting these goals aren’t in conflict.

This study has several important limitations. Because it’s cross-sectional, we can’t prove that eating sustainably causes better health—only that they’re associated. People with metabolic syndrome might have changed their diets after diagnosis, which could affect results. The study was conducted in Iran, so findings may not apply to other countries with different food systems and populations. Additionally, the study relied on people’s memories of what they ate, which can be inaccurate. The WISH score is based on only 13 food items, which is a simplified measure of a complex diet.

The Bottom Line

Based on this research, eating more sustainably and healthily appears to be beneficial for metabolic health. Focus on whole foods, plant-based options, and sustainably sourced items when possible. This is a moderate-confidence recommendation because the study shows association rather than definitive cause-and-effect. Anyone with metabolic syndrome or risk factors should work with their healthcare provider on dietary changes.

This research is most relevant to adults aged 35 and older, particularly those concerned about metabolic syndrome, heart health, or environmental impact. It’s especially relevant for people in Middle Eastern and similar populations where metabolic syndrome is common. However, the principles of sustainable, healthy eating likely benefit most adults. People with existing metabolic syndrome or its components should discuss dietary changes with their doctor.

Changes in metabolic markers like blood sugar and triglycerides can improve within weeks to months of dietary changes, though more significant improvements typically take 3-6 months. Sustained benefits require long-term adherence to healthier eating patterns.

Want to Apply This Research?

  • Track your WISH score by logging the 13 key food items: whole grains, legumes, nuts, fruits, vegetables, fish, olive oil, tea/coffee, and limiting red meat, processed meat, sugar-sweetened beverages, refined grains, and ultra-processed foods. Rate your daily adherence on a scale of 1-10.
  • Start by adding one sustainable food category per week—for example, week 1: add legumes to one meal, week 2: increase vegetables, week 3: choose whole grains. Use the app to set reminders and track which sustainable swaps feel easiest for you.
  • Monitor your WISH score weekly and track related health markers monthly if possible (waist circumference, energy levels, blood sugar if you have access to testing). Create a dashboard showing your trend over 3-6 months to visualize progress and maintain motivation.

This research shows an association between sustainable eating and lower metabolic syndrome risk, but does not prove that dietary changes will prevent or treat metabolic syndrome. This study was conducted in Iran and may not apply equally to all populations. Anyone with metabolic syndrome, prediabetes, heart disease, or other chronic conditions should consult with their healthcare provider or registered dietitian before making significant dietary changes. This information is for educational purposes and should not replace professional medical advice.