Ask Dana: How Much Fiber is Enough?


Dear Dana,

My doctor told me to increase my intake of fiber to help with blood sugars and weight loss.  I am not really sure what that means or how to do that.  I see lots of fiber supplements at the grocery store and I’m not sure if that is all I need to do.  And, then my next question is how much is enough or too much fiber?

Thank you for any tips.

– Sally Rosenfield, Wimberly, Texas


Dear Sally,

This is a great question. Fiber is the perfect nutrient to focus on to achieve both of your goals. 

High-fiber foods digest slower than low-fiber foods. This results in you feeling satisfied from a meal or snack for a longer amount of time.  If you are feeling full for longer, you eat less and weight loss may be achieved.  For diabetes management, a slower digested food means a slower rise of blood sugars after meals.  This allows for your insulin (either natural or injected) to better match the timing of your digested food and help to prevent large spikes of glucose levels.

Another benefit of fiber that many people notice is that with less hunger cravings and less spikes in blood sugars, cravings for high sugar foods subsides in a noticeable way.  This, of course, can facilitate even more weight loss and improvements in diabetes management.

Fiber can also work wonders to help lower unhealthy levels of low-density lipid (LDL) cholesterol.  High-fiber foods will help your body clear the unhealthy LDL molecules in your body in a natural way. Heart-healthy diets are always high-fiber diets for this reason.

high fiber foods
So, how do you achieve a high fiber diet and what does that mean?

First, we need to know what foods would include fiber.  Carbohydrates are the only foods that will naturally contain fiber. Any food that grows from the ground (or is made from grains and seeds) has the potential to be high in fiber, such as whole-grain carbohydrates. For breads, crackers and other carbohydrates, look for labels that include “whole grains.” The “whole grain” label indicates that the entire grain has been used in that food and that includes the fibrous outer shell of a grain.

It is important to note that “whole wheat” is not the same as “whole grain” and whole wheat foods are often not high in fiber at all as they may not include the fiber-rich portion of the grain.

Fruits and vegetables are also high in fiber, and the peel or rind of a vegetable or fruit is the most fibrous portion of the plant. Fruit that we take the peel off of – like a banana or melon – do not have as much fiber as a fruit that we eat whole – like blackberries or apple.  Vegetables often are very fibrous and are a good way to boost the fiber component of any meal.

Research does not show that fiber supplements provide the same benefits as naturally high-fiber foods. As much as possible you want to rely on high-fiber foods instead of foods with added fiber or taking fiber supplements.

How do we know how much fiber to have?  We measure fiber in grams as we do of carbohydrates. Fiber is listed on all food labels under “Carbohydrates.”   The recommendation is that men eat between 30-38 g of fiber a day and women eat between 21-25 g of fiber a day.  Notably, a typical diet in the United States includes only an average of 10-15g a day of fiber.  This is believed to be a contributing factor to several negative health outcomes, including obesity and Type 2 diabetes.

It can be difficult to know how much fiber you are eating on a regular basis unless you look at food labels.  Food diary apps like My Fitness Pal and Lose It include fiber grams in their logbooks.  Keeping track of the fiber you eat for one to two weeks can help you determine how you might boost your fiber.  For example, if you eat cereal in the mornings, find a high-fiber cereal that you enjoy and add fresh berries for an added punch of fiber.  Finding a high-fiber bread to use for sandwiches can easily boost your fiber at lunch.  Adding lentils or beans to dinner plans will increase your fiber tremendously.  Small changes in food choices and combinations can boost your fiber intake significantly.

With a high fiber intake, you will notice that mealtime blood sugars do not spike quite as high, and you will need less insulin.  This is something to keep in mind for mealtime insulin injections.  Very often, you may need to subtract fiber grams from your total carbohydrate grams if you are counting carbs for insulin.  Additionally, a high-fiber meal will take longer to digest; thus, the timing of your mealtime insulin will need to be adjusted.   Both of these adjustments may take time to perfect but will ultimately result in terrific outcomes.

Adding fiber to your daily meals is always a positive habit to embrace.  A registered dietitian can help guide you to make further adjustments to your nutrition. Providers at IDS are well versed on the ways high fiber diets can help your diabetes management as well.  Give us a call if you need any guidance or support!