- For many years, we’ve known that there is a strong link between type 2 diabetes and obesity, also known as ‘diabesity.’
- Diabesity is currently treated through a combination of different options, including healthy lifestyle modifications such as following a healthy diet, and medications like metformin.
- A new study found that following a healthy diet high in fiber may provide better outcomes for people with diabetes than taking metformin.
For many years, we’ve known that there is a strong link between type 2 diabetes and obesity. So much so, researchers have coined the term “diabesity” for a person who has both conditions.
Diabesity is currently treated through a combination of weight loss, healthy lifestyle changes, blood sugar monitoring, and certain medications, such as metformin.
Healthy lifestyle modifications for treating diabetes include getting enough physical activity and eating a healthy diet.
Now a new study published in the journal Frontiers in Microbiology reports that eating a healthy diet high in fiber may provide better outcomes for people with diabetes than taking metformin.
High-fiber diet lowers BMI, blood sugar, promotes healthy gut bacteria
For this study, researchers recruited 48 adults who were recently diagnosed with type 2 diabetes, and who were also overweight or obese.
Study participants were randomly selected to either follow a high-fiber diet without medication or take metformin alone for 84 days.
At day 84, researchers found that participants on the high fiber diet had a lower baseline-adjusted mean BMI, and experienced a lower hemoglobin A1C (HbA1c) — a test that checks your average blood sugar levels within the last 3 months — when compared to those in the metformin group.
Additionally, they discovered that participants in the high-fiber diet group also showed changes in their gut microbiome, compared to the metformin-only group.
By day 28, high-fiber diet participants increased the amount of the beneficial bacteria Bifidobacterium and Lactobacillus in their gut microbiome, and lowered the amount of
Past studies show that eating a high-fat diet can cause an increase in Bilophila wadsworthia in the microbiome, and overgrowth of this bacteria can lead to metabolic issues like type 2 diabetes.
Food is info for the microbiome
Medical News Today had the opportunity to speak with Mir Ali, MD, bariatric surgeon, bariatric medicine specialist, and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, about this study.
Ali, who was not involved in this study, commented that he was not surprised by its findings.
“We’ve long known that diet plays a very important role in the management of both diabetes and obviously obesity,” he continued. “This is just supporting evidence that it can dramatically make a difference.”
MNT also spoke with Monique Richard, MS, RDN, LDN, a registered dietitian nutritionist and owner of Nutrition-In-Sight, who was also not involved in this study.
Richard said that these study findings are a great reminder that food is not simply fuel, but also information for the body and its microbial community.
“The findings offer an interesting window into how dietary fiber may influence the gut microbiome and microbial metabolism,” she explained.
“My takeaway, and confirmed in my office daily, is that fiber deserves a much bigger place in the conversation about diabetes care as part of comprehensive, individualized treatment, not as a replacement for prescribed medication. Food and medication are not competing strategies, but often critically important complementary parts of care.”
–Monique Richard, MS, RDN, LDN
Further research needed
Richard said due to the small participant size of the study, she would caution readers not to jump to the conclusion by interpreting this as evidence that fiber is better than metformin.
“This was a small, single-center study involving 48 participants, with only 12 assigned to metformin, and the dietary intervention included prescribed fiber products and dietary guidance,” she detailed. “We need larger, longer studies to understand how these findings translate to everyday eating patterns and longer-term outcomes.”
Ali agreed and said he would like to see a larger study breaking it down into what types of fiber are more beneficial than others, such as fruits vs vegetables.
“There’s a lot of variability, and when you just say high fiber diet, that’s a broad class,” he continued. “So further research into the types of food that may be most beneficial and what exactly it is that’s going on in the body that’s improving these conditions.”
How can I add more fiber to my diet?
For readers who want to add more fiber to their diet, Richard said to first think about fiber as a family of nutrients, not a single substance.
“Soluble, insoluble, viscous, fermentable, and resistant-starch fibers have different properties,” she explained. “Food sources often provide several types at once, along with polyphenols, minerals, vitamins, and other compounds that may work together.”
“I encourage people to think about adding fiber-rich foods they enjoy, rather than overhauling their entire diet overnight,” Richard added. “Fiber is found in a wide variety of plant foods, so there are plenty of ways to build it into familiar meals and cultural food traditions.”
Richard provided a few practical places to start adding more fiber to diet:
- “Give beans, lentilsand peas a regular place at the table. Add lentils to soup or chili, beans to tacos or salads, or chickpeas to a grain bowl. Don’t have time to cook dried beans (often most economical), frozen or canned beans are convenient, affordable, and are an option as well.
- Choose whole fruits more often. Berries, pears, apples, and oranges provide fiber along with water and other beneficial nutrients. Enjoy the whole fruit, after washing, rather than relying on juice or fruit packed in syrup.
- Try swapping whole grains for refined grains. Try oats at breakfast, barley in soup, wild rice, whole-grain bread, or whole grain pasta mixed in with your regular pasta. These provide beta-glucan, a soluble fiber associated with improved cholesterol and glycemic outcomes.
- Add vegetables wherever they fit. Toss greens into eggs, add frozen vegetables to a stir-fry, or build a meal around roasted vegetables. Fresh, frozen, and canned options can all contribute.
- Add seasoning, flavor and benefits with these powerful plants. Onions, garlic, leeks, asparagus, and chicory root contain fibers such as inulin and fructans that can support certain microbes.
- Don’t forget nuts and seeds. Sprinkle chia seeds, ground flaxseed, or toasted nuts into oatmeal, yogurt, or salads, on top of casseroles, or for snacks.”
“The general principle is to build fiber into foods you already eat, slowly and consistently,” Richard said. “You don’t need expensive powders, specialty products, or a completely different way of cooking to get started.”
“Increase fiber gradually and drink enough fluids, especially if you’re making a substantial change,” she added. “A sudden increase can cause gas, bloating, or discomfort, and some people need a more tailored approach because of gastrointestinal conditions, swallowing difficulties, or other medical considerations.”
