A far-reaching new study from the Harvard T.H. Chan School of Public Health found a clear connection between a plant-based diet and a lowered risk of developing type 2 diabetes. Previous research has linked vegetarian diets to improved health outcomes, but this study was the first to differentiate between a healthy plant-based diet and a diet that with little or no meat but that includes not-so-healthy sweetened foods and beverages.
The Long-Term Impact of What We Eat
The researchers behind the study examined the diets of over 200,000 health professionals living across the United States. The participants, who were enrolled in three long-term studies, regularly filled out questionnaires on their diet, lifestyle, medical history, and new disease diagnoses.
After the T.H. Chan School of Public Health researchers evaluated participants’ diets over a 20-year period, they created a plant-based diet index (PDI) by assigning positive scores to plant-derived foods, and negative scores to animal-derived foods, such as…
- Dairy
- Eggs
- Fish and seafood
- Poultry
- Red meat
- Animal fats
They also created two further indexes, one designed to highlight healthy plant-derived foods such as whole grains, fruits, vegetables, nuts, legumes, vegetable oils, and tea and coffee, and one that highlighted unhealthful plant-derived foods, such as fruit juices, sweetened beverages, refined grains, potatoes, and sweets and desserts.
Emphasis on Healthful Plant-Based Foods
Using these indexes, they found that eating a healthy, plant-based diet lowered participants’ risk of developing diabetes by 34%. Eating a less healthy vegetarian diet, including foods like refined 
grains, potatoes, and sugar-sweetened beverages, for instance, still reduced the risk of developing diabetes, but only by 16%.
“A shift to a dietary pattern higher in healthful plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts, and seeds, and lower in animal-based foods, especially red and processed meats, can confer substantial health benefits,” said Frank Hu, senior author of the study.
Even A Small Shift Helps
Interestingly, the researchers also found a connection between slight decreases in consumption of animal-derived foods—as minimal as shifting from 5-6 servings daily to 4 servings daily—could lower rates of diabetes.
According to Ambika Satija, lead author of the study, their findings indicate that “even moderate dietary changes in the direction of a healthful plant-based diet can play a significant role in the prevention of type 2 diabetes.”
Why a Plant-Based Diet Improves Your Health
The study’s authors believe the reason plant-based diets lower your risk of type 2 diabetes could have to do with the nutritional profile of the foods that make up such a diet. Plant-based diets are high in…
- Fiber
- Micronutrients such as magnesium
- Antioxidants
- Unsaturated fatty acids
Plant-based diets may also encourage and support a healthy gut microbiome. All in all, Ambika Satija said, their findings offer further evidence that plant-based diets play a crucial role in chronic disease prevention.
Sources
http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002039
