Dietary Fiber: The Underrated Nutrient

What Is Dietary Fiber?

Dietary fiber consists of plant-based food components that the human small intestine cannot digest. It passes largely undigested into the large intestine. There are two main types:

• Soluble fiber forms a gel-like substance when it comes into contact with water. It is found primarily in oats, legumes, apples, and flaxseeds.
• Insoluble fiber binds water and increases stool volume. It is abundant in whole grains, vegetables, and nuts.

Most plant-based foods contain both types in varying proportions. A varied diet therefore typically covers both forms.

How Much Fiber Do You Need Per Day?

The Swiss reference values (FSVO 2022) state 30 g of fiber per day for adults aged 18 to 65, and 25 to 30 g from age 66. The World Health Organization (WHO) recommends that adults consume at least 25 g of naturally occurring dietary fiber per day. In Switzerland, average intake is only 20.7 g per day (mean for adults aged 18 to 75, national nutrition survey menuCH 2014/15). According to the same survey, 87% of adults do not reach 30 g.

What Role Does Dietary Fiber Play in Nutrition?

Dietary fiber is an important part of a balanced diet. The WHO and the Swiss reference values give guide values for daily intake. Nevertheless, fiber is lacking in most dietary routines. In sports nutrition in particular, the focus is often placed exclusively on protein, while fiber receives little attention.

Short-Chain Fatty Acids (SCFAs)

In the large intestine, soluble fiber is fermented by gut bacteria. This process produces short-chain fatty acids (SCFAs), particularly butyrate, propionate, and acetate. A review by Koh et al. (2016) in Cell described SCFAs as metabolites of bacterial fermentation. Research into their significance is evolving rapidly.

Which Foods Contain the Most Fiber?

Flaxseeds (27 g/100 g) and legumes are among the most fiber-rich foods. A single serving of lentils provides more than half of the reference value of 30 g.

Food	Fiber per 100 g	Type
Flaxseeds	27 g	soluble & insoluble
Lentils (cooked)	8 g	soluble
Chickpeas (cooked)	7 g	soluble & insoluble
Oats	10 g	predominantly soluble
Whole grain bread	7 g	predominantly insoluble
Broccoli	3 g	insoluble
Apples (with skin)	2.4 g	soluble (pectin)
Almonds	12 g	predominantly insoluble

Legumes and seeds are among the most fiber-rich foods. A single serving of lentils (200 g cooked) provides around 16 g of fiber. That is more than half of the daily recommendation.

How Can You Eat More Fiber?

The best approach is to increase fiber intake slowly to avoid discomfort. A sudden increase can be unpleasant.

• Step 1: Switch to oats or whole grain bread at breakfast. Add 1 tablespoon of flaxseeds to your muesli or yogurt.
• Step 2: Include a serving of legumes at lunch. Lentil soup, chickpea salad, or beans as a side dish are simple options.
• Step 3: Add more vegetables to your dinner plate. Gradually replace refined grain products with whole grain alternatives.
• Generally: Increase your fluid intake alongside your fiber intake. Fiber binds water.

Conclusion

Dietary fiber is one of the most underrated components of nutrition. The Swiss reference values state 30 g per day. Most people in Switzerland do not reach this value. The good news: With targeted, small adjustments, daily intake can be significantly increased.

High-Fiber Foods for Everyday Use

If you want to boost your daily fiber intake with high-quality plant-based products, here are some examples from the bunaroba range:

• Organic Wheatgrass: 44 g fiber per 100 g. One of the most fiber-dense plant foods available.
• Barley Grass: 39 g fiber per 100 g. A caffeine-free addition with a high fiber content.
• Organic Hemp Protein: 21 g fiber per 100 g (6.3 g per serving). Combines protein and fiber.
• Organic Protein Powder Nature / Vanilla: 12 g fiber per 100 g (3.6 g per serving).

These products blend easily into smoothies, muesli, or shakes and help you reach the recommended 30 g per day.

Good to know: Pure whey protein (isolate) contains no fiber. If you rely on whey, you need to get all of your fiber from other sources.

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Sources:

• Swiss Society for Nutrition SGE (2026). Dietary fiber. Presentation, 9 pages (in German; slide 7: Swiss reference values for nutrient intake, FSVO 2022). sge-ssn.ch
• World Health Organization (2023). WHO updates guidelines on fats and carbohydrates. News release, 17 July 2023. who.int
• von Blumenthal F, Schönenberger KA, Huwiler VV, Stanga Z, Pestoni G, Faeh D (2025). Dietary fibre intake in the adult Swiss population: a comprehensive analysis of timing and sources. Journal of Nutritional Science, 14, e27. DOI: 10.1017/jns.2025.6
• Schönenberger KA, Huwiler VV, Reber E, Mühlebach S, Stanga Z, Pestoni G, Faeh D (2024). Dietary fibre intake and its association with ultraprocessed food consumption in the general population of Switzerland: analysis of a population-based, cross-sectional national nutrition survey. BMJ Nutrition, Prevention & Health, 7(1), 26-37. DOI: 10.1136/bmjnph-2023-000727
• Koh A, De Vadder F, Kovatcheva-Datchary P, Bäckhed F (2016). From Dietary Fiber to Host Physiology: Short-Chain Fatty Acids as Key Bacterial Metabolites. Cell, 165(6), 1332-1345. DOI: 10.1016/j.cell.2016.05.041