Does consuming fiber really lower blood sugar? How many grams of fiber do you need each day? What’s the difference between soluble fiber and insoluble fiber?
Keri Glassman, MS, RD, CDN, the president and founder of Nutritious Life Meals, has written for many health magazines and often speaks about healthy diet on national television. I asked Keri to give Diabetes Health readers tips on increasing fiber intake and to explain the important role that fiber plays in our health. Her advice on adding fiber to your diet should not only help you keep your bowels regular, but also contribute to lower blood sugar and overall increased well-being.
Nadia: What is fiber, and why do people need fiber in their diet?
Keri: Dietary fiber includes the parts of plant foods that your body can’t digest or absorb. Therefore, it passes virtually unchanged through your stomach and small intestine and into your colon.
Dietary fiber is probably best known for its ability to prevent or relieve constipation by increasing the weight and size of the stool while softening it. But fiber can provide other health benefits as well. By keeping your bowels regular, fiber lowers your risk of digestive conditions, such as hemorrhoids, irritable bowel syndrome, and the development of small pouches in the colon.
Finally, eating a lot of fibrous foods aids in weight loss. High-fiber foods generally require lots of chewing, which gives your brain more time to tell your stomach that you’re full, making you less likely to overeat. A high-fiber diet tends to make a meal feel larger and linger longer, so you stay full longer. High-fiber diets also tend to be less “energy dense,” which means that they have fewer calories for the same volume of food.
Nadia: How much fiber do we need each day?
Keri: The amount actually varies for men and women. Men need about 30 to 38 grams per day, while women need 21 to 25 grams.
Nadia: We know that there is soluble fiber and insoluble fiber, but what is the difference?
Keri: Fiber is often classified into two categories: fiber that doesn’t dissolve in water (insoluble fiber) and fiber that does dissolve in water (soluble fiber).
Soluble fiber retains water and turns to gel during digestion, thereby slowing the process of digestion as well as the absorption of nutrients. That’s why you feel full longer! It can help lower blood cholesterol and glucose levels. You can find soluble fiber in oats, peas, beans, apples, citrus fruits, carrots, barley, and psyllium.
Insoluble fiber, on the other hand, speeds the passage of food through the stomach and intestines and adds bulk to the stool. Consequently, it’s a great remedy for constipation or irregular bowels. Whole-wheat flour, wheat bran, nuts, and many vegetables are good sources of insoluble fiber.
The bottom line: Both types of fiber are important components of a balanced diet.
Nadia: How does fiber affect people with diabetes?
Keri: When fiber enters your body, your body handles it differently than it does refined carbohydrates such as white flour. Fiber molecules are not broken down; instead, the fiber passes through your digestive system intact. This means that insulin is not required to digest fiber, so foods high in fiber are less likely to cause a spike in blood sugar. It’s a great perk for those who have diabetes.
Maintaining a diet that is high in fiber may also help control blood sugar and blood cholesterol levels by lowering low-density lipoprotein (“bad cholesterol”). Because fiber helps control blood sugar, it can reduce the risk of developing type 2 diabetes as well as heart disease.
Nadia: We’ve heard that for people with celiac disease, fiber supplements work well. Why is that?
Keri: For people with celiac disease, staying regular is sometimes a problem, so fiber can be very important. Whether it is problems with diarrhea or with constipation, our fibrous friends attack all ends! As we’ve said, fiber is one of the best ways to combat digestive issues. However, some gluten-free products are made from flours, such as tapioca flour, that are low in fiber. That’s why people who suffer from celiac disease sometimes turn to fiber supplements. There are plenty of gluten-free foods that can help you get your recommended dose of fiber, but if you suffer from celiac disease and find it easiest to take fiber supplements, they are a perfectly viable option. Adding Konsyl original flavor to a morning smoothie or even sprinkling it over a salad are easy ways to use a supplement without drinking it. You can learn more about Konsyl
Nadia: What are some other easy ways to get more fiber into my diet?
Keri: Does your breakfast usually consist of a bowl of cereal? If you tend to reach for that box of sugary cereal in the morning, try switching to a whole-grain, fiber-rich cereal instead. Smart Bran, Babara’s, and Kashi all make breakfast cereals that are low in sugar and high in fiber. Oatmeal is also a great, fiber-rich breakfast option. Just stay away from the varieties with added sugars! If you want to jazz it up, add some cinnamon.
Having a sandwich for lunch? Ditch the white bread and replace it with whole-grain bread! As a general rule, switching your “white carbs” for whole-grain carbs will increase your daily intake of fiber. So switch white pasta for whole wheat, shoot for brown rice in place of white rice, or make an adventurous leap to quinoa, spelt, or wheat berries. All of them are great whole-grain sources of fiber.
Need that afternoon munchie to crunch? Skip the chips and try a handful of whole-grain crackers, which often have more fiber than those greasy chips. Even better: switch to a bag of cut-up veggies or roasted, unsalted nuts. Veggies, such as peppers and carrots, will give you that needed crunch, but with an extra burst of fiber and minimal calories. If you’re opting for the nuts, don’t go too nuts, if you know what I mean. Stick to the recommended portion size (usually 1 ounce), because the fat and calories in nuts can add up quickly.
Regarding dinner, peas, please! Peas, beans, and lentils are all great sources of fiber. If you don’t like them on their own, try adding them to your salads.
Got the late night munchies? Swap your usual ice cream or chips for a bag of air-popped popcorn, another great source of fiber. Lastly, fruits and veggies are awesome sources of fiber-filled snacks. Those with diabetes, however, should be aware that the sugar content in fruits is often very high. Berries are a great option for lower-sugar, high-fiber fruits.
If you’re just looking to just sneak in a little extra fiber without making any real changes in your meal choices, try sprinkling flax seeds or chia seeds on your yogurt, oatmeal, cereal, or anything else you can think of. Both are great sources of fiber and are very mild in flavor.
Nadia: Thank you very much, Keri, for your insights on the value of including fiber in our diet.