To lower your risk of type 2 diabetes, eat a healthy plant-based diet full of fruits, vegetables, legumes, and nuts – and drink coffee, according to a new study from Harvard's School of Public Health, and avoid processed foods full of refined carbs and added sugar. Researchers from the Department of Nutrition at Harvard T.H. Chan School of Public Health published the study in the scientific journal Diabetologia.

With cases of type 2 diabetes predicted to reach 700 million globally by 2045, the study was designed to offer accessible solutions for individuals to lower their risk factors. The research found that eating more plant-based foods such as vegetables, fruits, legumes nuts, seeds, and drinking coffee could help minimize the lifetime risk of developing Type 2 diabetes.

“While it is difficult to tease out the contributions of individual foods because they were analyzed together as a pattern, individual metabolites from consumption of polyphenol-rich plant foods like fruits, vegetables, coffee, and legumes are all closely linked to a healthy plant-based diet and lower risk of diabetes,” Lead Author of the Study and Professor Frank Hu said.

The study aimed to identify the metabolite profiles associated with different plant-based diets and investigate possible associations between those profiles and the risk of developing T2D. Metabolites are the substances used or produced by the chemical processes of breaking down or metabolizing foods. Metabolite profiling is now the gold standard for measuring how a person's diet impacts their health since it's possible to measure the presence of different metabolites in a biological sample.

Currently, 90 percent of diabetes cases diagnosed are type 2 diabetes – meaning related to diet, exercise and lifestyle choices, as opposed to genetically driven.

Disease in adults has more than tripled since 2000, with cases increasing from150 million globally in 2000 to over 450 million in 2019, and cases are projected to reach 700 million in 2045.  In the US alone, one in three adults has diabetes and another 88 million have what is known as "prediabetes" which is still reversible, but a metabolic condition that includes insulin resistance and that can lead to diabetes.

What is a healthy plant-based diet?

In the latest study, Dr. Hu and his researchers analyzed 10,684 people from three prospective groups including the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professionals Follow-up Study. Participants filled out food and diet questionnaires that the researchers scored and separated into groups based on the three plant-based indexes of each:

  • Group 1 ate a diet rich in healthy plant foods such as fruits and vegetables
  • Group 2 ate unhealthy plant foods such as fruit juices, sweets, and refined grains
  • Group 3 ate a diet high in animal foods including fish, dairy, eggs, and meat.

Healthy and unhealthy plant-based foods were differentiated since healthy plant-based foods can lower the risk of Type 2 diabetes, and cardiovascular disease, whereas unhealthy plant-based foods full of added sugar and refined carbs increased the risk of heart disease, type2 diabetes as well as certain cancers.

Researchers tested blood samples taken during the initial phase of the study in the late 1980s and 1990s to create a metabolic profile of each group. The team then compared these profiles with later instances of type 2 diabetes development. The researchers found that the participants who developed Type 2 diabetes in the follow-up periods recorded lower consumption levels of healthy plant-based foods such as vegetables, legumes, and whole fruit.

“Our findings support the beneficial role of healthy plant-based diets in diabetes prevention and provide new insights for future investigation,” the study authors concluded. “Our findings regarding the intermediate metabolites are at the moment intriguing but further studies are needed to confirm their causal role in the associations of plant-based diets and the risk of developing Type 2 diabetes.”

Plant-based diets lower disease risk

The Harvard study also noted that its participant sample limited the extent of its research, explaining that most of the participants were white, middle-aged men with a mean BMI of 25.6kg/m2, claiming that to complete the research, more diversity is necessary. The final research found that participants who followed more unhealthy plant-based or animal-based diets showed a higher chance of developing Type 2 diabetes as well as higher BMI, blood pressure, and cholesterol levels. The study also notes that these participants typically were less physically active and had a history of diabetes.

These findings join a growing portfolio of research that claims that plant-based diets can significantly decrease your risk of developing diabetes. One study found that consuming red and processed meats raised diabetes risks by 33 percent. Other research has found that adding certain foods such as whole grains, nuts, beans, and lentils to your diet could help prevent diabetes development.

New York City’s new mayor Eric Adams echoes the study by claiming that plant-based eating helped him overcome diabetes. In his book, Healthy, At Last, Adams details how vegan foods helped him lose 35 pounds, get off diabetes medication and improve his overall health. With diabetes becoming increasingly prevalent, plant-based solutions continue to become more important.

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