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Poor diets are driving a global diabetes epidemic 

In a groundbreaking study, researchers at the Friedman School of Nutrition Science and Policy at Tufts University have found that poor diets may be responsible for a staggering 70 percent of global type 2 diabetes cases. This figure is significantly higher than the 40 percent estimated in previous studies. The experts say this difference may be attributed to the inclusion of new information in their analysis, as well as updated data on dietary habits.

One of the key factors leading to the higher percentage of type 2 diabetes cases linked to poor diets is the first-ever inclusion of refined grains in the analysis. Refined grains, such as white rice and wheat, were identified as one of the top contributors to the global diabetes burden. 

Furthermore, the updated data in the study was based on national individual-level dietary surveys, rather than agricultural estimates, which may have provided a more accurate assessment of people’s dietary habits.

Overall, the experts found that poor diets may be responsible for over 14.1 million cases of type 2 diabetes worldwide in 2018. The investigators, however, acknowledge the uncertainty surrounding these new estimates, noting that they can be further refined as new data becomes available. 

Despite the uncertainty, the study provides valuable insights into the impact of dietary factors on the global prevalence of type 2 diabetes and underscores the need for targeted interventions to address these factors. The research is published in the journal Nature Medicine.

Why the study matters

As the global incidence of type 2 diabetes continues to rise, these findings have significant implications for public health policy, healthcare professionals, and the private sector. By identifying key dietary contributors, such as refined grains, stakeholders can develop strategies and initiatives to promote healthier dietary choices, ultimately helping to curb the devastating impact of type 2 diabetes on individuals, families, and healthcare systems worldwide.

As scientific understanding of the relationship between diet and type 2 diabetes evolves, and as new data emerges, it will be critical for researchers to continue refining these estimates. In doing so, they can help inform future efforts to address the growing burden of type 2 diabetes.

“Our study suggests poor carbohydrate quality is a leading driver of diet-attributable type 2 diabetes globally, and with important variation by nation and over time,” said study senior author Professor Dariush Mozaffarian. “These new findings reveal critical areas for national and global focus to improve nutrition and reduce devastating burdens of diabetes.”

How the research was conducted

To develop their model, the researchers utilized data from the Global Dietary Database, population demographics from various sources, global type 2 diabetes incidence estimates, and information on how food choices affect individuals living with obesity and type 2 diabetes from multiple published papers.

The analysis revealed that poor diets contribute to a larger proportion of total type 2 diabetes incidence in men compared to women, in younger adults compared to older ones, and in urban residents compared to their rural counterparts at the global level.

Regionally, Central and Eastern Europe and Central Asia, particularly Poland and Russia, experienced the highest number of type 2 diabetes cases linked to diet. This is likely due to their diets, which tend to be rich in red meat, processed meat, and potatoes. Latin America and the Caribbean, especially Colombia and Mexico, also had a high incidence of diet-related type 2 diabetes cases, attributed to the consumption of sugary drinks, processed meat, and low intake of whole grains.

By contrast, South Asia and Sub-Saharan Africa showed a lower impact of diet on type 2 diabetes cases. However, Sub-Saharan Africa witnessed the largest increase in type 2 diabetes cases due to poor diet between 1990 and 2018. Among the 30 most populated countries studied, India, Nigeria, and Ethiopia had the fewest cases of type 2 diabetes related to unhealthy eating.

Study first author Meghan O’Hearn, who conducted this research while a PhD candidate at the Friedman School, warned that “left unchecked and with incidence only projected to rise, type 2 diabetes will continue to impact population health, economic productivity, health care system capacity, and drive health inequities worldwide.” She emphasized that these findings could help inform nutritional priorities for clinicians, policymakers, and private sector actors as they encourage healthier dietary choices to address the global epidemic.

What is Type 2 diabetes?

Type 2 diabetes is a chronic metabolic condition that affects the way the body processes glucose (sugar), which is its primary source of energy. It is the most common form of diabetes, accounting for approximately 90-95% of all diabetes cases. The condition is characterized by insulin resistance, wherein the body’s cells do not respond properly to insulin, a hormone produced by the pancreas that enables cells to take up glucose from the bloodstream.

Risk factors for type 2 diabetes 


The risk of developing type 2 diabetes increases with age, especially after the age of 45. However, due to factors such as obesity and sedentary lifestyles, the condition is increasingly being diagnosed in younger individuals, including children and adolescents.

Family history

Having a close family member, such as a parent or sibling, with type 2 diabetes increases the risk of developing the condition.


Being overweight or obese is one of the most significant risk factors for type 2 diabetes, as excess fat can cause insulin resistance.

Physical inactivity 

Leading a sedentary lifestyle increases the risk of type 2 diabetes, as regular physical activity helps maintain a healthy weight and regulate blood sugar levels.


Certain ethnic groups, including African Americans, Hispanics, Native Americans, Asian Americans, and Pacific Islanders, have a higher risk of developing type 2 diabetes compared to non-Hispanic whites.

Gestational diabetes

Women who have had gestational diabetes during pregnancy are at an increased risk of developing type 2 diabetes later in life.

Symptoms, management, and prevention 

Symptoms of type 2 diabetes may include increased thirst, frequent urination, unexplained weight loss, fatigue, blurred vision, slow-healing sores, and frequent infections. However, some people with type 2 diabetes may not exhibit any symptoms, which makes regular check-ups and screenings crucial for early detection and management.

Managing type 2 diabetes typically involves a combination of lifestyle changes, such as maintaining a healthy diet, engaging in regular physical activity, and losing excess weight. In some cases, oral medications or insulin injections may be required to help regulate blood sugar levels.

Prevention strategies for type 2 diabetes include adopting a healthy, balanced diet that is rich in fruits, vegetables, whole grains, lean proteins, and healthy fats; engaging in regular physical activity; maintaining a healthy weight; and avoiding tobacco products. Regular check-ups and screenings can also help detect the early signs of type 2 diabetes and facilitate prompt intervention to prevent or delay the onset of the condition.


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