A major review of 36 studies found that people who eat plant-based diets have a significantly lower risk of developing type 2 diabetes. Vegan diets showed the strongest protection, reducing risk by 35%, while vegetarian diets cut risk by 32%. However, not all plant foods are equal - healthy plant foods like vegetables, fruits, and whole grains were protective, but unhealthy plant foods like sugary drinks and refined grains actually increased diabetes risk by 13%. This research suggests that choosing the right plant foods matters more than simply avoiding animal products.

The Quick Take

  • What they studied: Whether eating plant-based diets (vegetarian, vegan, or mostly plants) affects the risk of developing type 2 diabetes
  • Who participated: Analysis of 36 different studies involving hundreds of thousands of adults from around the world, published between 1999-2025
  • Key finding: Vegan diets reduced diabetes risk by 35%, vegetarian diets by 32%, but unhealthy plant foods increased risk by 13%
  • What it means for you: Focus on healthy plant foods like vegetables, fruits, and whole grains rather than just avoiding meat - quality matters more than labels

The Research Details

This was a meta-analysis, which means researchers combined results from 36 separate studies to get a bigger, clearer picture. They looked at observational studies that followed people over time to see who developed type 2 diabetes based on their eating patterns. The researchers specifically examined different types of plant-based eating: vegan (no animal products), vegetarian (no meat but some dairy/eggs), and plant-based indices that scored how much people emphasized plant foods over animal foods.

By combining many studies, researchers can spot patterns that might be missed in smaller individual studies. This approach gives us more confidence in the results because it includes diverse populations and different ways of measuring plant-based eating.

The study included research spanning over 25 years and used established methods for combining study results. However, the results varied between studies, and some findings had wide confidence intervals, meaning we should interpret results with appropriate caution.

What the Results Show

The analysis revealed that plant-based diets consistently reduced type 2 diabetes risk, but the type and quality of plant foods mattered enormously. Vegan diets showed the strongest protection with a 35% risk reduction, though this result had some statistical uncertainty. Lacto-ovo vegetarian diets (including dairy and eggs) provided a more statistically reliable 32% risk reduction. When researchers looked at plant-based diet scores rather than strict categories, they found that overall plant emphasis reduced risk by 18%, while healthy plant foods specifically cut risk by 24%. Most surprisingly, unhealthy plant-based diets actually increased diabetes risk by 13%.

The dose-response analysis showed that the more people emphasized healthy plant foods, the lower their diabetes risk became - this relationship was almost perfectly linear. Conversely, the more unhealthy plant foods people ate, the higher their risk climbed, also in a linear fashion.

These findings align with previous research showing plant-based diets can improve blood sugar control and insulin sensitivity. However, this study is among the first to clearly demonstrate that unhealthy plant foods can be just as harmful as animal products for diabetes risk.

The studies were observational, so they can’t prove that plant-based diets directly prevent diabetes - other healthy behaviors might explain some benefits. The definition of ‘plant-based’ varied between studies, and most participants were from Western countries, limiting global applicability.

The Bottom Line

Focus on healthy plant foods like vegetables, fruits, whole grains, nuts, and legumes rather than simply avoiding animal products. Limit processed plant foods like sugary drinks, refined grains, and packaged snacks. A well-planned vegetarian or vegan diet appears beneficial, but a poorly planned one may be harmful.

Anyone interested in diabetes prevention, especially those with family history or other risk factors. People already eating plant-based should ensure they’re choosing nutrient-dense options rather than processed alternatives.

The studies followed people for several years, suggesting that consistent long-term dietary patterns matter more than short-term changes. Benefits likely accumulate over months to years of sustained healthy eating.

Want to Apply This Research?

  • Track daily servings of healthy plant foods (vegetables, fruits, whole grains, legumes, nuts) versus unhealthy plant foods (sugary drinks, refined grains, processed snacks)
  • Set a goal to replace one processed food item daily with a whole plant food, such as swapping chips for nuts or soda for fruit
  • Monitor the ratio of healthy to unhealthy plant foods weekly, aiming for at least 80% of plant foods to come from whole, minimally processed sources

This information is for educational purposes only and should not replace professional medical advice. Consult your healthcare provider before making significant dietary changes, especially if you have diabetes, prediabetes, or other health conditions.