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The Difference Between Soluble and Insoluble Fiber: A Complete Guide…

Updated: May 6, 2023

Insoluble vs Soluble Fiber: What's the Difference?



Fiber is an essential part of a healthy diet. It is a type of carbohydrate that the body cannot digest or absorb. Instead, it passes through the digestive system mostly intact, providing a variety of health benefits. There are two main types of fiber: insoluble fiber and soluble fiber.

Insoluble fiber is known for its ability to promote regularity and prevent constipation. It is found in foods such as whole wheat, bran, nuts, and many vegetables. Insoluble fiber adds bulk to the stool, making it easier to pass through the digestive system. This type of fiber also helps to keep the digestive system healthy by feeding the beneficial bacteria in the gut.


Soluble fiber, on the other hand, dissolves in water to form a gel-like substance in the digestive tract. It is found in foods such as oats, barley, beans, and many fruits and vegetables. Soluble fiber can help to lower cholesterol levels by binding to cholesterol and preventing it from being absorbed into the bloodstream. This type of fiber can also help to regulate blood sugar levels by slowing down the absorption of carbohydrates.

Here are some key differences between insoluble and soluble fiber:

  1. Digestion - Insoluble fiber is not digested by the body and passes through the digestive system mostly intact. Soluble fiber, on the other hand, dissolves in water and forms a gel-like substance in the digestive tract.

  2. Function - Insoluble fiber adds bulk to the stool and promotes regularity. Soluble fiber can help to lower cholesterol levels and regulate blood sugar levels.

  3. Food sources - Insoluble fiber is found in foods such as whole wheat, bran, nuts, and many vegetables. Soluble fiber is found in foods such as oats, barley, beans, and many fruits and vegetables.

  4. Benefits - Insoluble fiber can help to keep the digestive system healthy by feeding the beneficial bacteria in the gut. Soluble fiber can help to lower cholesterol levels, regulate blood sugar levels, and promote a feeling of fullness.

So, how much fiber do you need and how can you get it?


The recommended daily intake of fiber is 25 grams for women and 38 grams for men. To get enough fiber, aim to include a variety of high-fiber foods in your diet, such as whole grains, fruits, vegetables, nuts, and seeds. Be sure to drink plenty of water as well, as fiber needs water to work properly in the digestive system.


Foods high in insoluble fiber:

  • Whole grains (brown rice, quinoa, bulgur, etc.)

  • Nuts and seeds (almonds, flaxseeds, chia seeds, etc.)

  • Vegetables (broccoli, carrots, Brussels sprouts, etc.)

  • Fruits (apples, pears, berries, etc.)

Foods high in soluble fiber:

  • Oats and oat bran

  • Beans and legumes (lentils, chickpeas, black beans, etc.)

  • Fruits (oranges, bananas, prunes, etc.)

  • Vegetables (sweet potatoes, spinach, kale, etc.)

The daily recommended intake of fiber varies depending on age, gender, and activity level. Here are some general guidelines for daily fiber intake:

For men:

  • Age 19-50: 38 grams per day

  • Age 51 and older: 30 grams per day

For women:

  • Age 19-50: 25 grams per day

  • Age 51 and older: 21 grams per day

It's important to gradually increase your fiber intake and drink plenty of water to help your body adjust. Some people may experience bloating or gas when they first increase their fiber intake, but these symptoms should improve over time.

Here are some examples of what a daily intake of fiber could look like for men and women:


For men:

  • Breakfast: 1 cup of oatmeal (4 grams of fiber) with 1 medium banana (3 grams of fiber) and 1 tablespoon of chia seeds (5 grams of fiber)

  • Snack: 1 medium apple (4 grams of fiber) with 1 ounce of almonds (3 grams of fiber)

  • Lunch: Turkey sandwich with whole grain bread (4 grams of fiber) and a side salad with mixed greens (2 grams of fiber)

  • Snack: 1 cup of raw carrots (3.5 grams of fiber) with 2 tablespoons of hummus (2 grams of fiber)

  • Dinner: Grilled salmon with quinoa (5 grams of fiber) and roasted broccoli (2 grams of fiber)

Total fiber intake for the day: 38.5 grams


For women:

  • Breakfast: 1 cup of Greek yogurt (0 grams of fiber) with 1/2 cup of mixed berries (3 grams of fiber) and 2 tablespoons of ground flaxseed (4 grams of fiber)

  • Snack: 1 small orange (3 grams of fiber) with 1 ounce of walnuts (2 grams of fiber)

  • Lunch: Veggie wrap with whole grain tortilla (3 grams of fiber) and a side of baby carrots (2 grams of fiber)

  • Snack: 1/2 cup of edamame (4 grams of fiber)

  • Dinner: Baked chicken with quinoa (5 grams of fiber) and sautéed kale (2 grams of fiber)

Total fiber intake for the day: 25 grams


More foods!


Soluble Fiber:

  • Oatmeal (1 cup cooked): 4 grams

  • Lentils (1 cup cooked): 4 grams

  • Apples (1 medium): 2 grams

  • Oranges (1 medium): 2 grams

  • Pears (1 medium): 2 grams

  • Flaxseeds (1 tablespoon): 2 grams

  • Chia seeds (1 tablespoon): 1.5 grams

  • Carrots (1 medium): 1 gram

Insoluble Fiber:

  • Brown rice (1 cup cooked): 3.5 grams

  • Quinoa (1 cup cooked): 2.5 grams

  • Whole wheat bread (1 slice): 2 grams

  • Almonds (1/4 cup): 4 grams

  • Walnuts (1/4 cup): 2 grams

  • Broccoli (1/2 cup): 2.5 grams

  • Brussels sprouts (1/2 cup): 2 grams

  • Sweet potato (1 medium): 4 grams

  • Popcorn: 3.5 grams serving


 

By incorporating these fiber-rich foods into your diet, you can improve your gut health, regulate blood sugar and cholesterol levels, and reduce the risk of chronic diseases.

Both soluble and insoluble fiber play important roles in maintaining good health. Soluble fiber can help regulate blood sugar and cholesterol levels, while insoluble fiber promotes regular bowel movements and aids in weight management. By incorporating a variety of fiber-rich foods into your diet, you can reap the benefits of both types of fiber and improve your overall health.


ABOUT ME I received my training from the Institute for Integrative Nutrition and am a National Board-Certified Health Coach. I learned about more than one hundred dietary theories and studied a variety of practical lifestyle coaching methods. Drawing on this knowledge, I will help you create a completely personalized “roadmap to health” that suits your unique body, lifestyle, preferences, and goals. Learn more about my training and my unique approach to health coaching on my website or social platforms!


In Health, and 25 grams,


Amanda





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