Vegetarian Diets and Diabetes Risk: Unveiling the Impact on Body Weight

The Effect of Vegetarian Diets on Diabetes Risk and Weight. Summary of research by Serena Tonstad, Terry Butler, Ru Yan, and Gary E. Fraser

This 2007 study analyzed data from over 60,000 Seventh-day Adventists to compare the risk of type 2 diabetes and body weight across different vegetarian diets versus nonvegetarian diets. The specific vegetarian diets evaluated were:

- Vegan: No animal products

- Lacto-ovo: Dairy and eggs only

- Pesco: Dairy, eggs, and fish (no red meat/poultry)

- Semi: Occasional meat

The key findings of the study included:

- Vegans, lacto-ovo vegetarians, pesco-vegetarians, and semi-vegetarians all had substantially lower rates of type 2 diabetes compared to nonvegetarians - from 16-49% lower risk.

- The reductions were greatest in vegans and lacto-ovo vegetarians. Pesco and semi had smaller but still significant reductions in diabetes risk.

- BMI was lowest in vegans (23.6) and incrementally higher through each diet type up to nonvegetarians (28.8) showing the link between plant-based diets and lower weight.

- The lower diabetes risk was partly but not wholly explained by the lower BMIs of vegetarians. The vegetarian diets themselves offered protective effects against diabetes development.

In summary, this well-designed study demonstrates clear correlations between vegetarian diets and substantially reduced likelihood of having type 2 diabetes. The stricter the vegetarian diet, the greater the risk reduction and BMI benefits. The results argue for the health protective effects of vegetarian eating patterns.

Tonstad, S., Butler, T., Yan, R., & Fraser, G. E. (2009). "Type of Vegetarian Diet, Body Weight, and Prevalence of Type 2 Diabetes." Diabetes Care, 32(5), 791–796. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2671114/