What the Research Says About Diet and Type 1 Diabetes in Adults

A comprehensive review published in 2025 examined 41 studies on diet and Type 1 diabetes in adults, looking at everything from blood sugar control to quality of life. Researchers found that medical nutrition therapy—working with food as part of diabetes management—is a key piece of staying healthy with Type 1, but the research on which specific diets work best has been scattered and inconsistent.

The review included observational studies (where researchers tracked what people ate and their outcomes), randomized controlled trials (where people were assigned to different diets), and studies that looked at how diet affects mental health and well-being.

Low-carbohydrate diets stood out in the research. People who followed a low-carbohydrate approach saw their HbA1c drop by 0.3–0.9%, and their total daily insulin doses decreased by approximately 15–20%. Importantly, this reduction in carbohydrates did not lead to more severe low blood sugar episodes—a concern many people have when changing their diet.

Structured carbohydrate counting programs—where people carefully track and plan their carbohydrate intake—also improved blood sugar levels and cholesterol profiles. A low-fat vegan diet showed similar benefits for both blood sugar and lipid (cholesterol) control.

Mediterranean-style eating and other plant-based approaches mainly improved diet quality and overall well-being, even if they didn't produce the most dramatic drops in HbA1c. The research suggests that better metabolic control was generally linked to eating fewer carbohydrates, but the connection between diet type and outcomes varied across studies.

As more people live longer with Type 1 diabetes, a separate review examined nutrition research specifically for adults age 65 and older. The findings revealed a significant gap: there are very few studies focused on diet and nutrition in this population. Researchers identified only 11 original studies dedicated to older adults with Type 1 diabetes.

Current clinical guidelines offer little specific guidance tailored to older adults, even though this group faces unique challenges—managing multiple health conditions, changes in appetite and ability to eat, and shifts in lifestyle. Experts say much more research is needed to understand what nutritional approaches work best as people age with Type 1 diabetes.

Beyond traditional dietary approaches, emerging research is exploring how technology and structured education can help people manage their diet and diabetes more effectively. Studies are testing whether smartphone apps combined with artificial intelligence can improve self-management skills, and whether specialized training programs can help people—especially older adults—get more benefit from continuous glucose monitors (CGM devices that track blood sugar throughout the day).

These innovations aim to make diabetes management more personalized and accessible, though results from these studies are still being gathered.

If you're an adult living with Type 1 diabetes, this research suggests that working with your healthcare team to find a sustainable eating approach—whether low-carbohydrate, carbohydrate counting, plant-based, or Mediterranean—can meaningfully improve your blood sugar control and overall health. The key is finding an approach that fits your lifestyle and that you can stick with long-term.

The fact that different diets showed benefits reminds us that there's no one-size-fits-all solution. What works best for one person may differ from what works for another. If you're considering changes to your diet, talking with a diabetes educator or registered dietitian who specializes in Type 1 can help you choose an approach that's right for you and make sure it's balanced and safe.

Origin: National Institutes of Health (NIH) | (.gov) (News report). Evidence: News report, corroborated with 4 indexed studies. Type1Cure is an information and intelligence hub, not a medical advice service. This article summarizes published research and does not provide diagnosis, treatment, or personal medical guidance. Always talk to your own care team before changing anything about your Type 1 diabetes management.