• Shop AG1

    • AG1Best Seller

      Our daily core supplement blend.

    • AG1 Travel Packs

      Our core supplement blend in convenient single servings.

    • Research & Testing

      Clinical research and peer-reviewed science, explained.

    • Ingredients

      Understanding our science-backed ingredients.

    • Quality Standards

      The rigorous testing behind every batch.

    • What is AG1?

      Learn what makes AG1 unique.

    • Benefits

      Discover the everyday benefits of making AG1 part of your routine.

    • Blog

      The latest from our team on health, science, and wellness.

    • Find AG1 Near You

      Search for AG1 in retailers near you.

Sign In
Shop
Science
Explore
Sign In

Shop AG1

  • AG1Best Seller

    Our daily core supplement blend.

  • AG1 Travel Packs

    Our core supplement blend in convenient single servings.

  1. Home
  2. Blog
  3. Gut Health & Digestion
  4. How Much Fibre Per Day Do You Really Need?

How Much Fibre Per Day Do You Really Need?

Not sure how much fibre you should be eating each day? Learn the recommended intake, what happens if you get too little or too much, and how to find the right balance for your digestion and overall health.

Written by nutrition expert Evan Lynch, MSc
3 MIN READ — 05/20/2026

What We'll Cover

  • 01.

    Why Fibre Intake Matters

  • 02.

    How Much Fibre Per Day Is Recommended?

  • 03.

    What Happens If You Eat Too Little Fibre?

  • 04.

    Can You Eat Too Much Fibre?

  • 05.

    How to Increase Fibre Safely

Fibre is one of the most important nutrients for digestive health—yet one of the most commonly under-consumed. So how much fibre do you actually need each day?

Key Takeaways

  • 01.

    Most adults don't meet the recommended daily fibre intake, despite its importance for digestion and overall health.

  • 02.

    Around 25–30 g per day is a practical target, though individual needs can vary slightly.

  • 03.

    Both the amount and diversity of fibre matter—aiming for a wide range of plant foods supports gut health.

  • 04.

    Too little fibre can impact digestion, while increasing it too quickly may lead to discomfort.

  • 05.

    A balanced approach—combining whole foods with convenient options like high fibre products—can help support consistent intake.

Meet Our Expert

Evan Lynch, MSc

MSc Sports Nutrition – Registered Dietitian, Head of Nutrition Europe at AG1

Evan Lynch is a CORU-registered dietitian with a BSc in Food Science and Health, a Postgraduate Diploma in Dietetics, and an MSc in Sports Nutrition. Evan is the Head of Nutrition for Europe at AG1, where he supports strategic nutrition direction, education, and evidence-based communication. Alongside this role, he runs a private practice supporting clients across sports nutrition, gastrointestinal disorders, geriatric nutrition, and weight management.

Why Fibre Intake Matters

While general recommendations exist, the right amount isn’t just about hitting a number. It’s about consistency, variety, and finding an approach that works for your lifestyle.

Fibre comes exclusively from plant foods and plays a central role in digestive health. It supports:

  • Regular bowel movements
  • Stool bulk and consistency
  • A balanced gut environment

But beyond digestion, fibre also influences the gut microbiome and can even impact your immunity.

Research shows that dietary diversity matters just as much as total fibre intake. Consuming 30 or more different plant foods per week—including vegetables, fruit, whole grains, legumes, nuts, seeds, herbs, and spices—is associated with greater gut microbial diversity.

In practice, this means that focusing only on grams of fibre isn't enough. The quality and variety of your diet are just as important.

How Much Fibre Per Day Is Recommended?

The European Food Safety Authority (EFSA) recommends an Adequate Intake of 25 g per day for healthy adults, based on its role in supporting normal bowel function.

Many national guidelines suggest aiming closer to 30 g per day for optimal health. However, most people fall short of this:

  • Men typically consume around 18–24 g
  • Women around 16–20 g

That gap reflects modern dietary patterns—often low in whole plant foods and higher in refined, processed options. The good news: meeting your fibre needs is both achievable and sustainable when approached through simple habits and variety.

Fibre-rich food examples (approximate values):

  • Medium banana: ~3 g
  • 1 tbsp chia seeds: ~5 g
  • 1 tbsp ground flaxseed: ~3 g
  • 2 slices wholegrain bread: ~6 g
  • Bowl of porridge oats (40 g dry): ~4 g

Sample high-fibre day:

  • Breakfast: Porridge with chia seeds (~9 g)
  • Lunch: Wholegrain sandwich with chicken, cheese & mixed vegetables (~7 g)
  • Snack: Yogurt with ground flaxseed and berries (~4 g)
  • Dinner: 1 medium salmon fillet + lentils + diced vegetables (~9 g)

What Happens If You Eat Too Little Fibre?

Low fibre intake can affect digestion in several ways. Common signs include:

  • Irregular bowel movements
  • Constipation
  • Reduced stool bulk

Over time, a low fibre diet is also associated with:

  • Lower gut microbiome diversity
  • Less stable blood glucose responses
  • Lower overall diet quality

In many cases, low fibre intake reflects a broader lack of plant foods—meaning you may also be missing out on other important nutrients and compounds.

Can You Eat Too Much Fibre?

While fibre is beneficial, more isn't always better—especially if intake increases too quickly. Suddenly consuming large amounts of fibre can lead to:

  • Bloating
  • Gas
  • Abdominal discomfort

This is particularly true for fermentable fibres, which are broken down by gut bacteria.

For most people, the issue isn't 'too much fibre' overall—but too much, too fast. A gradual increase allows your digestive system to adapt more comfortably.

Does Too Much Fibre Cause Diarrhea?

In some cases, yes. Very high fibre intake—especially from certain types of fibre or supplements—can speed up intestinal transit and lead to looser stools.

This can happen when:

  • Fibre is increased rapidly
  • Fluid intake is too low
  • Large amounts of specific fibres (like certain fermentable fibres) are consumed

That said, fibre doesn't inherently cause diarrhea. It's more about how it's introduced and balanced within your diet. Adjusting intake gradually and staying well hydrated usually resolves these issues.

How to Increase Fibre Safely

If your current intake is low, the best approach is to increase fibre gradually. Start with:

  • Small, consistent changes: switch to wholegrain options
  • Adding more plant foods: fruits, vegetables, legumes
  • Focusing on variety, not just quantity

Hydration is also key. Fibre works best when paired with adequate fluid intake. In practice, this might look like:

  • Adding seeds or fruit to breakfast
  • Including vegetables in multiple meals
  • Choosing high fibre snacks
  • Using convenient options (like fibre-containing products) to support consistency

Final Thoughts on How Much Fibre per Day

So, how much fibre do you really need? For most adults, 25–30 g per day is a practical and evidence-based target. But beyond the number, what matters most is how you get there:

  • Through a variety of plant foods
  • Built into your daily routine
  • Supported by consistent habits

Fibre intake doesn't need to be perfect—it just needs to be consistent. And with the right approach, it's one of the simplest ways to support your digestion and overall health long term.

FAQ

Question

Expert Answer

How much fibre per day do I actually need?

Most adults should aim for around 25–30 g of fibre per day. This recommendation is based on supporting normal digestion and overall health. Individual needs may vary slightly, but this range is a practical and achievable target for most people.

What happens if I don't eat enough fibre?

Low fibre intake can lead to digestive issues like constipation and irregular bowel movements. Over time, it may also impact gut microbiome diversity and overall diet quality, as fibre-rich foods are often key sources of important nutrients.

Can eating too much fibre be harmful?

Fibre itself isn't harmful, but increasing intake too quickly can cause bloating, gas, or discomfort. The key is to build intake gradually and ensure you're drinking enough water to support digestion.

Does too much fibre cause diarrhea?

In some cases, yes—especially if fibre intake increases suddenly or if certain types of fibre are consumed in large amounts. Gradually increasing intake and maintaining hydration can help prevent this.

Is 25 g of fibre per day enough?

Yes—25 g per day is the baseline recommendation from EFSA for healthy adults. Many guidelines suggest aiming closer to 30 g per day for additional benefits, but consistency and variety are just as important as hitting a specific number.

Get the scoop on wellbeing science delivered to your inbox.

SHOP

  • The Pouch
  • Travel Packs

REVIEWS

  • AG1 Reviews on Trustpilot
  • Third-Party Testing
  • Informed Sport
  • Cologne List

LEARN MORE

  • Ingredients
  • Benefits
  • FAQs
  • AG1 Reviews

ABOUT

  • About Us
  • Leadership
  • Refer Friends
  • Partners
  • Impact Report
  • Accessibility Statement

CONTACT

  • My Account
  • Track My Order
  • Help
  • Careers
  • My Affiliate Account

Connect

Join Our Newsletter


© AG1


Food supplements are not a substitute for a balanced and varied diet and a healthy lifestyle. Do not exceed the indicated daily intake. Keep out of reach of children. Please inform and consult your doctor before consuming this product. Not suitable for children and adolescents under 18 years, pregnant or breastfeeding women. Refrain from taking other food supplements containing zinc. Persons taking anticoagulant medication should seek medical advice before consuming vitamin K-containing supplements.

* Genuine reviews from customers who received a review link after purchase.

**Offer valid for new customers only upon signing up for a prepaid 3-month AG1 subscription. Regular price £199. Welcome Kit and gifts provided once. Subscription automatically renews unless cancelled beforehand.

↡ Ongoing survey of 3,000+ AG1 customers after 12+ days of use, 2024.

§ In a third-party, observational study conducted on 35 healthy adults ages 25-48 assessing the self-perceived efficacy of AG1 over the course of 3 months. The study was conducted on a similar version of AG1's continually evolving formulation. The study results are transferable because of comparable ingredients and amounts.

○ Ongoing survey of customers from 12 European countries who have been taking AG1 for an average of 9 days.

⬥ AG1 single subscriptions price and dose-matched average aggregated prices in 9 individual nutritional supplement categories with comparable ingredients. The prices of the individual supplements are the average prices of three individual products available online for each compared category, each with comparable ingredients. To ensure a fair basis for comparison, where the comparison products have different dosages, the prices were mathematically adjusted to correspond to the dosage contained in AG1. The 9 compared categories are vitamin B12, folate (Methylfolate), vitamin C, vitamin E, bacterial cultures, zinc, coenzyme Q10, greens powder and fibre.

Research Studies
a. In a triple-blind, randomised, placebo-controlled parallel-designed clinical trial evaluating nutrient biomarkers and microbiome shifts in 105 healthy adults ages 20-59 over the course of 12 weeks.
b. In a double-blind, randomised, placebo-controlled 2-week cross-over clinical trial assessing microbiome shifts in 20 active adults ages 19-37.
c. In a double-blind, randomised, placebo-controlled 2-week cross-over clinical trial assessing microbiome shifts of 24 healthy adults with occasional GI distress ages 26-59.
d. In a double-blind, randomised, placebo-controlled cross-over clinical trial assessing bioavailability in 16 healthy adults ages 18-42 over the course of 8 hours.
The studies were conducted on a similar version of AG1's continually evolving formulation. The transferability of the study results is ensured because of comparable ingredients and amounts.

◊ Key health benefits:

(1) Immune system: With vitamins A, C, B6 and B12 as well as folate, zinc, copper and selenium, AG1 contributes to the normal function of the immune system. Vitamin C contributes to maintain the normal function of the immune system during and after intense physical exercise. 200 mg Vitamin C taken daily in addition to the recommended daily dose (80 mg) contributes to the normal function of the immune system during and after intensive physical activity.

(2) Energy levels: Vitamins C, B6, B12, riboflavin, niacin, pantothenic acid and magnesium contribute to normal energy-yielding metabolism and to the reduction of tiredness and fatigue. Magnesium contributes to electrolyte balance. Biotin, zinc and chromium contribute to normal macronutrient metabolism.

(3) Digestion: Calcium contributes to the normal function of digestive enzymes. With vitamin A, biotin, riboflavin and niacin, AG1 contributes to the maintenance of normal mucous membranes (e.g. intestinal mucosa).

(4) Focus; Mental performance; Psychological function; Nervous system: With pantothenic acid, AG1 contributes to normal mental performance. Zinc contributes to normal cognitive function. With vitamins C, B6, B12, B1, B3 and B7 AG1 contributes to normal psychological function and to normal functioning of the nervous system. Calcium contributes to normal neurotransmission.

‡ Additional health benefits:

(5) Muscles: With calcium and magnesium, AG1 contributes to normal muscle function.

(6) Cell Protection: With vitamins E and C as well as riboflavin, zinc, copper and selenium, AG1 contributes to the protection of cells from oxidative stress. Phosphorus contributes to normal function of cell membranes. Folate, Vitamin B6 and B12 contribute to normal homocysteine metabolism.

(7) Skin, hair & nails: With vitamins A, as well as riboflavin, niacin, biotin and zinc, AG1 contributes to the maintenance of normal skin. Vitamin C contributes to normal collagen formation for the normal function of skin. Copper contributes to normal connective tissue. Vitamin B7, zinc and selenium contribute to the maintenance of normal hair. Zinc and selenium contribute to the maintenance of normal nails.

(8) Hormonal system: With vitamin B6, AG1 contributes to the regulation of hormonal activity. Zinc contributes to the maintenance of normal testosterone levels in the blood. Selenium contributes to the normal thyroid function. With chromium, AG1 contributes to the maintenance of normal blood glucose levels.

Your privacy is our priority. Learn more:  

  • Privacy
  • Terms & Conditions
  • Legal Notices
© AG1