Researchers studied 883 middle-aged men at risk for type 2 diabetes over three years. Some received coaching to eat healthier foods like vegetables, whole grains, and fish, while others didn’t. The men who got coaching and actually changed their eating habits significantly lowered their diabetes risk. Interestingly, the benefits were strongest for men with genes that made them more likely to develop diabetes. This shows that even if diabetes runs in your family, the foods you choose to eat really matter and can help protect your health.
The Quick Take
- What they studied: Whether teaching men to eat healthier foods could reduce their chances of developing type 2 diabetes, and whether this worked differently for people with different genetic risks
- Who participated: 883 men aged 50-75 years old who were overweight and showed early signs of diabetes (prediabetes). Half received healthy eating coaching for 3 years, and half didn’t
- Key finding: Men who improved their diet by eating more vegetables, whole grains, and fish reduced their diabetes risk by about 33%. Men who ate more unhealthy foods like processed meats increased their risk by 82%. The benefits were especially strong for men with genes that made them more vulnerable to diabetes
- What it means for you: Your food choices matter more than you might think, especially if diabetes runs in your family. Even if you have genes that increase diabetes risk, eating better foods can significantly protect you. This suggests that lifestyle changes can overcome some genetic disadvantages
The Research Details
This was a three-year study where researchers followed 883 men who were at risk for type 2 diabetes. The men were split into two groups: one group received group-based coaching sessions to help them eat healthier foods, while the other group received no special coaching. At the start and end of the study, researchers asked the men detailed questions about what they ate using a food frequency questionnaire—basically a checklist of foods where they reported how often they ate each item.
The researchers also looked at each man’s genetic risk by analyzing 76 different genes known to affect diabetes risk. They divided the men into groups based on whether they had low, medium, or high genetic risk. This allowed them to see if the diet coaching worked the same way for everyone or if it worked better for some people than others.
At the end of three years, the researchers checked who had developed type 2 diabetes using standard medical tests (blood sugar levels and a test called HbA1C that shows average blood sugar over time).
This study design is important because it shows real-world results from actual people making changes over a long period of time. Rather than just looking at one meal or one week, researchers tracked what people actually ate over three years. By comparing the coaching group to the non-coaching group, they could see if the coaching actually caused the changes. By also looking at genetic risk, they discovered something crucial: the diet changes helped everyone, but especially helped people whose genes put them at highest risk.
This study has several strengths: it included a large number of participants (883 men), followed them for a long time (3 years), and compared a coached group to a control group. The researchers used standard medical tests to diagnose diabetes rather than relying on what people reported. However, the study only included men aged 50-75, so results might be different for women or younger people. Also, the men had to be willing to participate in a lifestyle study, which might mean they were more motivated than the average person.
What the Results Show
Men who received the lifestyle coaching made significant changes to their eating habits. They ate more whole-grain products, vegetables, and healthy oils compared to their baseline eating patterns and compared to the control group. The researchers identified two main eating patterns: a healthy pattern (high in vegetables, whole grains, and fish) and an unhealthy pattern (high in processed meats, sausages, and low-fiber products).
The most important finding was that men who followed the healthy eating pattern at the end of the study had a 33% lower risk of developing type 2 diabetes compared to those who didn’t follow this pattern. In contrast, men who followed the unhealthy eating pattern had an 82% higher risk of developing diabetes. These differences were statistically significant, meaning they weren’t due to chance.
When the researchers looked specifically at men with high genetic risk for diabetes, the benefits of healthy eating were even more pronounced. Men with high genetic risk who ate the healthy pattern had substantially lower diabetes risk. This suggests that for people with a family history of diabetes, diet becomes even more important as a protective factor.
The study also showed that the lifestyle intervention successfully changed eating behaviors in the coaching group. Compared to the control group, men receiving coaching increased their consumption of recommended foods like whole grains, vegetables, and healthy oils. The control group (those not receiving coaching) showed minimal changes in their eating patterns over the three years. This demonstrates that structured group-based coaching can actually help people change their food choices in meaningful ways.
These findings align with previous research showing that diet quality is important for diabetes prevention. However, this study adds new information by showing that these diet-diabetes associations appear to be especially strong in people with genetic predisposition to diabetes. Previous studies suggested that lifestyle changes could help prevent diabetes, but this research clarifies that people with genetic risk factors may benefit even more from dietary improvements, suggesting that genes and diet work together to determine diabetes risk.
This study only included men aged 50-75, so the results might not apply to women, younger people, or older adults. The men who participated were likely more motivated than average since they volunteered for a lifestyle study, which could mean the results are better than what would happen in the general population. The study relied on people’s memory of what they ate (through questionnaires), which can be inaccurate. Additionally, the study couldn’t prove that diet changes directly caused the lower diabetes risk—only that they were associated with it. Other factors like exercise, weight loss, or stress levels might have also played a role.
The Bottom Line
If you’re at risk for type 2 diabetes (especially if it runs in your family), focus on eating more vegetables, whole grains, and fish while reducing processed meats and low-fiber foods. Consider joining a group-based program or working with a counselor who can help you make these changes, as the study showed group coaching was effective. These changes appear to work for everyone but may be especially protective if you have a family history of diabetes. Confidence level: Moderate to High—this is based on a well-designed study with a large number of participants followed over three years.
This research is most relevant for men aged 50-75 who are overweight and have prediabetes or a family history of type 2 diabetes. However, the general principles (eating more vegetables, whole grains, and fish; eating less processed meat) apply to anyone wanting to reduce their diabetes risk. Women and younger people should note that while this study didn’t include them, similar dietary principles are recommended for diabetes prevention across all ages and genders. If you have been diagnosed with type 2 diabetes or have severe health conditions, consult your doctor before making major dietary changes.
The study tracked changes over three years, so expect that meaningful improvements in diabetes risk take time. You might notice improvements in weight, energy levels, or blood sugar readings within weeks to months of changing your diet, but the full protective effect against diabetes develops over a longer period. Don’t expect overnight results, but consistent healthy eating over months and years can significantly reduce your risk.
Want to Apply This Research?
- Track daily servings of vegetables, whole grains, and fish consumed, plus weekly servings of processed meats. Aim for at least 3-5 servings of vegetables daily, 2-3 servings of whole grains, 2-3 servings of fish per week, and limit processed meats to 1-2 servings per week or less
- Use the app to set a weekly goal for trying one new vegetable or whole grain recipe. Log your meals daily and get feedback on whether you’re moving toward the healthy eating pattern (more vegetables, whole grains, fish) or the unhealthy pattern (more processed meats, low-fiber foods). Set reminders for meal planning and grocery shopping focused on healthy foods
- Track changes in your eating patterns monthly rather than daily to see the bigger picture. Every 3 months, review your food logs to identify which healthy foods you’re eating consistently and which unhealthy foods you’re still consuming too much of. If possible, get periodic blood sugar tests (fasting glucose or HbA1C) to see if your dietary changes are improving your actual diabetes risk markers
This research shows associations between diet and diabetes risk but does not constitute medical advice. If you have prediabetes, diabetes, or a family history of diabetes, consult with your healthcare provider or a registered dietitian before making significant dietary changes. This study was conducted in men aged 50-75 and may not apply to all populations. Individual results vary based on genetics, overall lifestyle, and other health factors. Always work with qualified healthcare professionals to develop a personalized nutrition and diabetes prevention plan.