Published 12th October 2022

Should I try a high-fiber diet?

Fiber plays a vital role in promoting the health of your heart, gut, and metabolism.

It’s a carbohydrate, but your body can’t fully digest it, unlike most other carbs. Fiber has many important functions in your body, including serving as food for the bugs living in your gut.

The gut microbiome is the trillions of microorganisms that live in your gut and have a major impact on your overall health. 

In fact, ZOE scientists have identified 15 “good” gut bugs that are associated with indicators of good health and 15 “bad” gut bugs that are linked with worse health. 

In this article, we’ll take a closer look at the benefits and risks of a high-fiber diet and which foods to include.

At ZOE, we know a one-size-fits-all approach doesn’t work for nutrition. With the ZOE at-home test, you can learn about the “good” and “bad” bugs living in your gut, and which foods you can eat to promote the “good” bugs.

We’ll also analyze your blood sugar and blood fat responses to give you personalized nutrition advice tailored to your unique body.

To get started, take our free quiz.

Benefits

There are two main types of fiber: soluble and insoluble. 

Soluble fiber dissolves in water, while insoluble fiber doesn’t. They work differently, but they’re both important for your body to function properly. 

Gut health

Research indicates that fiber can improve the composition of your gut microbiome. This may benefit some people with gastrointestinal disorders, like irritable bowel syndrome (IBS) and inflammatory bowel disease.

A review of 35 studies found links between fiber from whole grains and greater numbers of the “good” bacteria Bifidobacterium and Lactobacillus — as well as lower levels of potentially dangerous bacteria, such as Escherichia coli, better known as E. coli.

Digestion

Several studies have shown that fiber can help at different stages of digestion. This includes breaking down and absorbing nutrients, improving food transit time, and helping with stool formation. 

Heart health

Researchers have linked high fiber intakes with a risk of heart disease and stroke that's reduced by nearly 25%.  

Also, a recent systematic review found that high intakes of fiber improve cholesterol levels and blood pressure for adults with heart disease or high blood pressure.

Plus, they found that a high intake of fiber may decrease the risk of early death by 25%.

Fiber may help heart health by lowering the absorption of “bad” cholesterol and triglycerides and improving the elasticity of blood vessel walls.  

Blood sugar control

Studies show that high-fiber diets are important in controlling blood sugar levels. Fiber helps slow the rate that blood sugar enters the bloodstream, helping prevent blood sugar spikes

Fiber also reduces inflammation, improves blood fat levels, and reduces the chance of premature death by 45% in adults with diabetes.  

What does a high-fiber diet look like?

Experts recommend that women consume about 25 grams of fiber every day and men about 35 g.

However, adults in the United States only consume around 16–18 g of fiber a day, which is far less than the recommended amount.

Getting enough fiber can be easy if you know what to eat. There are plenty of great high-fiber, low-cost options that are simple to fit into your diet. 

Below are some rich sources of fiber.

Vegetables

  • broccoli (5 g of fiber per cup)

  • Brussels sprouts (4 g per cup)

  • sweet corn (4 g per cup)

  • popcorn (4 g per 3 cups)

  • carrots (3 g per cup)

Fruits

  • avocado (10 g per cup)

  • raspberries (8 g per cup)

  • coconut (7 g per cup)

  • kiwi (5 g per cup)

  • apple (5 g per apple)

Grains

  • bulgur wheat (8 g per cup, cooked)

  • dark rye flour (7 g per quarter cup)

  • whole-wheat spaghetti (6 g per cup)

  • oats (4 g per half cup) 

  • rye crackers (3 g per 2 slices)

  • wheat germ (2 g per 2 tablespoons)

Legumes

  • green peas (9 g per cup)

  • lentils (16 g per cup)

  • black beans (14 g per cup)

  • edamame pasta (11 g per 50 g)

  • chickpeas (4 g per cup)

Nuts and seeds

  • chia seeds (10 g per ounce)

  • sunflower seeds (3 g per tablespoon)

  • almond flour (3 g per quarter cup)

  • peanuts (2 g per tablespoon)

Learn more about these and other high-fiber foods here.

Fiber supplements

While fiber supplements may seem like a simpler option, research suggests that most fibers in supplements don’t offer the same health benefits associated with a high-fiber diet. 

Plus, you lose out on the vital nutrients that come with food sources.

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Tips for adopting high-fiber diet

You may have some temporary, mild discomfort while your body adjusts to more fiber. Here are some ways to help minimize any problems.

Increase your fiber intake slowly

Getting more fiber has many benefits, but if you increase your intake too fast, it can cause:

  • gas and bloating

  • stomach cramps

  • diarrhea

  • constipation

  • nausea

  • feeling overly full

To avoid this, increase your fiber intake gradually. This way, your gut has time to adjust.

Increase your water intake

Both soluble and insoluble fiber need water to work well. Drink plenty of water regularly to make sure you don’t get constipated. 

Eat a diverse range of plants

Within the two main groups of fiber, there are several subtypes. To make sure you get the full range of fibers and the full range of benefits, aim to eat a variety of high-fiber plants. 

Also, the bugs living in your gut microbiome have different fiber preferences, so more diversity in fiber means you’re more likely to feed the “good” bugs in your gut.

Risks

As we mentioned, increasing your fiber intake too rapidly can cause some temporary discomfort. 

People with IBS and other gastrointestinal disorders should also be cautious when introducing more fiber into their diets. Different types of IBS benefit from different types of fiber. 

If you have a gastrointestinal disorder, speak with a healthcare provider before you make any big changes to your diet.

Summary

The long-term effects of eating more fiber are positive. Fiber acts as food for the bugs in your gut microbiome. Getting more fiber can lead to improved heart, metabolic, and gut health.

There are plenty of healthy high-fiber foods to add into your usual diet. And eating more vegetables instead of meat and dairy or fatty foods, like fried foods, is a great place to start.

While an increase in fiber is generally a good thing, introducing it too quickly can lead to some uncomfortable symptoms, such as bloating, gas, cramping, and constipation. 

To avoid these symptoms, increase your fiber intake gradually, stay hydrated, and eat a diverse range of plants.

At ZOE, we know a one-size-fits-all approach doesn’t work for nutrition. With the ZOE at-home test, you can learn about the “good” and “bad” bugs living in your gut, and which foods you can eat to promote the “good” bugs.

We’ll also analyze your blood sugar and blood fat responses to give you personalized nutrition advice tailored to your unique body.

To get started, take our free quiz.

Sources

Association between dietary factors and constipation in adults living in Luxembourg and taking part in the ORISCAV-LUX 2 survey. Nutrients. (2022). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8746799/ 

Dietary fibre and cardiovascular health: a review of current evidence and policy. Proceedings of the Nutrition Society. (2020). https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/dietary-fibre-and-cardiovascular-health-a-review-of-current-evidence-and-policy/D32A613205AE6F23509F2381379131F8

Dietary fibre and whole grains in diabetes management: systematic review and meta-analyses. Plos Medicine. (2020). https://pubmed.ncbi.nlm.nih.gov/32142510/

Dietary fiber, gut microbiota, and metabolic regulation—current status in human randomized trials. Nutrients. (2020). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7146107/

Dietary fiber in gastrointestinal health and disease. Nature. (2020). https://www.nature.com/articles/s41575-020-00375-4

Dietary fiber in irritable bowel syndrome (review). International Journal of Molecular Medicine. (2017). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5548066/

Dietary fiber is beneficial for the prevention of cardiovascular disease: an umbrella review of meta-analyses. Journal of Chiropractic Medicine. (2017). https://pubmed.ncbi.nlm.nih.gov/29276461/

Dietary guidelines for Americans 2015—2020 eighth edition. (2015). https://health.gov/sites/default/files/2019-09/2015-2020_Dietary_Guidelines.pdf

Fiber supplements and clinically proven health benefits: How to recognize and recommend an effective fiber therapy. Journal of the American Association of Nurse Practitioners. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5413815/

Food sources for dietary fiber. (n.d.). https://www.dietaryguidelines.gov/resources/2020-2025-dietary-guidelines-online-materials/food-sources-select-nutrients/food-0

Impact of gut bacteria on human health and disease. International Journal of Molecular Sciences. (2015). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425030/

Increasing fiber intake. (n.d.). https://www.ucsfhealth.org/education/increasing-fiber-intake

The impact of dietary fiber on gut microbiota in host health and disease. Cell Host & Microbe. (2018). https://www.cell.com/cell-host-microbe/fulltext/S1931-3128(18)30266-X 

Whole grains, dietary fibers and the human gut microbiota: a systematic review of existing literature. Recent Patents on Food, Nutrition & Agriculture. (2020). https://pubmed.ncbi.nlm.nih.gov/32178621/

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