Your Diet May Matter More Than Your Genes for Diabetes Risk

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Healthy lifestyle changes — especially improving diet — can significantly lower the risk of Type 2 diabetes in people with prediabetes, regardless of their genetic risk, according to a study published in the European Journal of Nutrition. Even if you have a family history of diabetes, adopting healthier eating habits can make a meaningful difference.

“The evidence on the interaction between genes and diet in the prevention of Type 2 diabetes is still limited and contradictory and mostly based on epidemiological studies,” wrote lead investigator Ulla Tolonen, a doctoral researcher at the University of Eastern Finland. “Some previous studies suggest that there is no interaction between the diet and genetic Type 2 diabetes burden and that everyone, regardless of their genetic risk for Type 2 diabetes, benefits from healthy lifestyle equally. However, there are also previous studies reporting an interaction between the diet and genetic risk of Type 2 diabetes.”

The current study enrolled men aged 50 to 75 with prediabetes and a body mass index (BMI) of 25 or higher from the Metabolic Syndrome in Men (METSIM) cohort. Participants were divided into two groups: One received a three-year group-based lifestyle counseling program, while the other acted as a control group (usual care). The team also divided participants into low or high genetic risk groups based on their genetic makeup.

People in the intervention group attended five to seven group sessions over a three-year period, with a focus on encouraging healthy food choices, including more whole grains, vegetables, fish, and healthier oils (such as vegetable oils, excluding tropical oils such as palm oil). At the same time, participants were encouraged to reduce processed meats (like sausages), red meat, and low-fiber and refined foods. Laboratory visits happened at the start and each subsequent year.

The control group only had lab visits at the start and end of the study, and they received one-time general lifestyle advice at baseline but no group sessions or online support.

Participants filled out a 47-item food questionnaire at baseline and year three. Foods were scored based on how often they were eaten. The team looked at changes in both healthy dietary patterns (like fruits, vegetables, fish, whole grains, low-fat dairy) and unhealthy dietary patterns (like fried foods, processed meats, sweets, white bread, high-fat cheese, pizza). They also tracked weight, BMI, blood sugar tests, exercise habits, smoking and alcohol intake.

At the end of the intervention, three key findings were revealed:

• Better food choices:
  • By the end of the three years, those in the lifestyle program ate more vegetables, whole grains, fish and healthy oils than at the start. They also cut back on red and processed meats and refined foods.
• Impact on diabetes risk:
  • People who followed a healthy dietary pattern had a 33% lower risk of developing Type 2 diabetes.
  • People who continued with an unhealthy dietary pattern had nearly double the risk of developing Type 2 diabetes.
• Genetics matter, but lifestyle still helps:
  • Even men who were at high genetic risk for diabetes saw benefits. The associations between diet and diabetes risk were strongest in this group, showing that lifestyle changes can help reduce risk — even when genes suggest a higher likelihood of disease.

“We need to find resource-efficient ways within health care to support these lifestyle changes. Group-based and online counseling is more resource-efficient than individual counseling,” said Tolonen. “Our new findings show that group-based and online counseling is sufficient to support lifestyle changes among individuals with a high genetic risk of Type 2 diabetes.”