Dietary fiber, also called roughage, is the indigestible part of plants. While it counts as a carbohydrate and theoretically has an energy value of roughly 3.57 to 4.12 calories per gram, because fiber is not digested, it actually counts as zero calories.

This article will cover the recommended intake levels for dietary fiber, why we want to reach those levels, the dangers of overconsumption, and which foods are richest in it.

Note that all recommended intake figures below are based on the needs of a 31 year old non-pregnant, non-lactating woman on a 2000 kilocalorie diet. Your personal requirements may differ (wildly). One way to figure out your individual needs, including calories per day, is the FooDosage Nutrition Calculator. It’s free, by the way.


Recommended Fiber Intake

The recommended intake of dietary fiber is 5% of your daily total calorie intake. In case of a 2000 kcal diet, this means roughly 24 grams a day.


Why we Need Enough of it

According to the National Academy of Sciences, dietary fiber reduces the risk of coronary heart disease and assists in maintaining normal blood sugar levels.

Additionally, maintaining an optimal fiber intake helps alleviate or ward against both constipation and diarrhea, and leads to soft and regular bowel movements.


Dangers of Overconsumption

Possible adverse effect of getting too much fiber in your diet are cramping, gas and  bloating.

If you increase your fiber intake too suddenly, perhaps after reading this article, you may experience diarrhea. You need to give your body time to adjust by increasing the intake in small increments, if you had almost no fiber in your diet previously.

Constipation and dehydration can be cause by a high fiber intake combined with simultaneous insufficient liquid intake. Be sure to drink enough water.

The extreme case is a bowel obstruction, caused by consuming too much fiber and/or not enough liquids. This is a serious health issue that requires medical attention.


Foods Richest in Dietary Fiber

In general, dietary fiber is found predominantly in (full) grains, bread, nuts, seeds, berries, and legumes. Some choice examples:

FooDosage Nutrition Calculator - Dietary Fiber Leaderboard

FooDosage Nutrition Calculator – Dietary Fiber Leaderboard


Wheat Bran

Example: Bob’s Red Mill Wheat Bran (Amazon)

Dietary Fiber per 100g: 42.8g (175% RDA)

Wheat bran may not be the tastiest of foods, and I would not recommend eating it out of the bag, but it makes for a nutritious and very fiber rich addition to other foods. Mix it into your yogurt, smoothie, spinach, or even burger patty, if you’re not getting enough fiber from “actual” foods that day.

Be sure to drink enough water.

Wheat bran is also an excellent source of:

  • Manganese – at 11.5mg / 100g (639% RDA) Warning: The Upper Limit is 11mg.
  • Magnesium – at 611mg / 100g (191% RDA)
  • Phosphorus – at 1013mg / 100g (145% RDA)
  • Selenium – at 77.6µg / 100g (141% RDA)
  • Copper – at 1mg / 100g (111% RDA)



Example: Bob’s Red Mill Organic Steel Cut Oats (Amazon)

Dietary Fiber per 100g: 10.6g (43% RDA)

Oats, a breakfast staple here at FooDosage, make for an excellent way to start the day. Not only is an oat porridge tasty, filling and full of energy that will sustain you until lunch, it’s also a great source of fiber. At 17g / 100g, its protein content is not too shabby either.

Note: Oats only achieve a protein completeness score of 81%. They are slightly deficient in the amino acid lysine. For those 17 grams to count completely, the deficiency needs to made up for by eating other foods rich in lysine.

Oats are also an excellent source of:

  • Manganese – at 4.9mg / 100g (273% RDA)
  • Phosphorus – at 523mg / 100g (75% RDA)
  • Copper – at 0.6mg / 100g (70% RDA)
  • Thiamin (B1) – at 0.8mg / 100g (69% RDA)
  • Magnesium – at 177mg / 100g (55% RDA)

Full article: Leading the Charts: Oats



Example: Palouse Brand Non-GMO Project Verified Pardina Lentils (Amazon)

Dietary Fiber per 100g (cooked): 7.9g (32% RDA)

Mmmh, Lentils. Another favorite here, especially if fried with bacon and crème fraîche. Rich in fiber and taste, while filling and hardy. Lentils also come with a respectable amount of Protein: 9g / 100g.

Protein completeness score: 86% (Deficient in Methionine & Cysteine)

Lentils are also a good source of:

  • Folate (B9) – at 181µg / 100g (45% RDA)
  • Copper – at 0.25mg / 100g (28% RDA)
  • Manganese – at 0.5mg / 100g (27% RDA)
  • Phosphorus – at 180mg / 100g (26% RDA)



Example: California Hass Organic Avocados (Amazon)

Dietary Fiber per 100g: 6.8g (28% RDA)

Avocados may not sport the highest fiber content, but they do bring a little color and variety to this list, don’t they?

I’m sure I don’t have to tell you about all the health benefits attributed to avocados. Are they all they’re hyped up to be? We’ll have a look at that later.

Update, April 30, 2017: We had a look at it, and while avocados are a great source of fiber, you should consider alternatives.

Avocados are also a decent source of:

  • Pantothenic acid (B5) – at 1.4mg / 100g (29% RDA)
  • Vitamin K – at 21µg / 100g (23% RDA)
  • Vitamin B6 – at 0.3mg / 100g (22% RDA)
  • Folate (B9) – at 89µg / 100g (22% RDA)


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Bon Appetit 🙂



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