When we talk about feeding dogs, protein and fat usually get most of the attention. Fibre tends to be forgotten about, but it can have a surprisingly important role in your dog’s digestion, gut health, weight and even their anal glands.

The right amount and type of fibre can help your dog produce comfortable, well-formed poos, support the helpful bacteria living in their gut and keep them feeling fuller after meals.

However, that does not mean every dog needs more fibre adding to their food.

Adding spoonfuls of pumpkin, vegetables or fibre supplements without looking at the rest of the diet can sometimes make things worse. Different types of fibre behave differently, and what helps one dog may cause wind, bloating or loose stools in another.

So, what exactly is fibre, and why does it matter for dogs?

What Is Fibre?

Fibre is the part of plant-based foods that is not fully broken down by your dog’s digestive enzymes in the small intestine.

Instead, it travels further through the digestive system, where it may absorb water, add bulk to the stool or be fermented by bacteria in the large intestine.

You may see fibre described in a few different ways.

Soluble fibre absorbs water and can form a soft, gel-like substance in the gut.

Insoluble fibre mainly adds bulk to the stool and helps food move through the digestive tract.

Fermentable fibre is used as a food source by bacteria in the large intestine.

Poorly fermentable fibre is less easily broken down by gut bacteria and mainly helps to increase stool bulk.

Many foods contain a mixture of these different fibre types, which is why two ingredients can have very different effects on your dog’s digestion.

For more information about the wider role of plant ingredients in canine diets, read The Canine Dietitian’s guide to carbohydrates in canine nutrition.

Fibre Helps Support Healthy Poos

One of the easiest ways to see the effect of fibre is by looking at your dog’s poo.

Some fibres absorb water and can help soften stools that are too dry or difficult to pass. Others add shape and bulk, which may help loose stools become better formed.

This is why fibre can sometimes help dogs at both ends of the spectrum, from constipation to soft stools.

However, it is not quite as simple as adding pumpkin power to every meal.

Too much fermentable fibre can cause gas, urgency, bloating or even looser stools. Large amounts of insoluble fibre may produce very bulky poos and can reduce how well some nutrients are absorbed.

Research comparing different fibre sources has shown that the type of fibre used can affect stool moisture, stool volume and overall digestibility. This is a good reminder that the type of fibre matters just as much as the amount.

Dogs can also naturally produce a firm first poo followed by a softer one later in the day. This does not always mean they need extra fibre. Exercise, excitement, stress, gut transit time and how many times they poo can all affect consistency.

Read more about why your dog’s poo may be firm in the morning but softer later in the day.

Fibre Feeds Helpful Gut Bacteria

Your dog’s gut is home to a huge community of bacteria, often referred to as the gut microbiome.

Some types of fermentable fibre act as food for these bacteria. When the bacteria break fibre down, they produce substances called short-chain fatty acids.

These substances help support the environment within the large intestine and provide energy for the cells lining the colon.

Studies in dogs have shown that changing the type and amount of fibre in the diet can affect the bacteria living in the gut and the compounds they produce.

That does not mean one particular ingredient is a miracle solution for gut health. A varied and carefully balanced mixture of different fibre sources may be more useful than relying on one trendy powder or supplement alone.

Can Fibre Help With Loose Stools?

It may sound strange to add fibre when a dog already has diarrhoea, but certain soluble fibres can soak up excess water and help firm stools up and become more consistent.

Psyllium husk is one example. Research has found that soluble fibre may be useful as part of the management of some dogs with ongoing large-bowel diarrhoea.

However, psyllium is not something that should automatically be added every time your dog has a soft poo.

Loose stools can be caused by lots of different things, including:

• A sudden diet change

• Eating too much food

• Too many treats or chews

• Rich or fatty foods

• Stress or excitement

• Parasites

• Infections

• Medication

• Food-responsive digestive problems

• Pancreatic or intestinal disease

If your dog regularly has diarrhoea, mucus, blood, urgency or accidents in the house, it is important to speak to your vet rather than repeatedly trying different supplements and switching diets

Fibre can be helpful, but it should not be used to cover up an underlying health problem.

Fibre and Weight Management

Fibre can also be useful when helping a dog lose weight.

It adds volume to food without contributing the same number of calories as fat. Some fibre-rich diets may also help dogs feel fuller and more satisfied after eating. It’s not uncommon for may weight loss and management diets to have up to 17% fibre ( on a dry matter basis) as opposed to the normal 2-5% for a healthy adult dog.

Studies have found that diets containing higher levels of protein and fibre can improve feelings of fullness and support weight loss in overweight dogs.

However, simply adding vegetables to an oversized portion will not make a dog lose weight.

Successful weight loss still depends on controlling the dog’s total calorie intake. This includes meals, treats, chews, scraps and anything used during training.

A proper weight-management plan should take into account:

• Your dog’s current weight

• Their ideal weight

• Body condition and muscle condition

• Daily calorie intake

• Treat allowance

• Age and activity levels

• Mobility problems

• Any medical conditions

• A safe rate of weight loss

You can find more useful tips in Soopa’s guide to helping your dog lose weight.

Fibre and Anal Gland Health

Fibre is often mentioned when dogs have problems with their anal glands.

The anal sacs sit on either side of the anus and should normally release small amounts of fluid when a dog passes a stool.

A comfortably firm and bulky poo may place gentle pressure around the anal sacs and help them empty naturally.

This is why improving stool consistency can sometimes help dogs that experience recurring anal gland problems.

However, harder and smaller poos are not always better for anal glands

Very dry, chalky stools can be uncomfortable and difficult to pass. This is sometimes seen in dogs eating diets containing a lot of bone.

The idea that extremely hard poos are automatically better for anal gland health is a myth. Dogs need stools that are well-formed but still comfortable to pass.

A small study published in 2025 found that dogs receiving a combined fibre and probiotic product experienced fewer recurring anal sac impactions than dogs that did not receive it. However, because the product contained both fibre and probiotics, it is not possible to say that fibre alone caused the improvement.

Find out more about fibre and anal glands here bum scooting, anal glands, diet and fibre.

It is also important to remember that scooting is not always caused by fibre or anal gland problems.

Dogs may scoot because of:

• Parasites

• Allergies

• Skin irritation

• Matted fur

• An anal sac infection

• An abscess

• Pain or swelling around the anus

Frequent scooting, licking, swelling, pain, blood or discharge should always be checked by a vet and any of the above ruled out before you start on a fibre crusade.

Which Foods Contain Fibre?

There are plenty of dog-friendly foods that contain fibre, including:

• Sweet potato

• Pumpkin

• Carrots

• Green beans

• Apples without the pips or core

• Oats

• Barley

• Beet pulp

• Ground flaxseed

• Psyllium husk

• Inulin

• Fructooligosaccharides

Each of these ingredients contains a slightly different mix of fibre.

Pumpkin, sweet potato and carrots, for example, contain both soluble and insoluble fibre alongside vitamins, minerals and plant compounds.

Soopa’s plant-based treats include ingredients such as sweet potato, pumpkin, carrot and papaya, making them an easy way to include naturally fibre-containing ingredients as part of your dog’s treat allowance. You can check these out here

Treats should ideally make up no more than around 10% of your dog’s daily calorie intake, with the majority of their nutrition coming from a complete and balanced main diet.

How Much Fibre Does a Dog Need?

There is no perfect fibre percentage that suits every dog.

The ideal amount will depend on your dog’s:

• Age

• Body weight

• Activity levels

• Current diet

• Stool quality

• Digestive health

• Medical conditions

• Individual tolerance

One dog may thrive on a higher-fibre diet, while another may develop gas, large stools or loose poos.

It is also worth remembering that the “crude fibre” figure on a dog food label does not show the total amount of fibre in the food.

Crude fibre is measured using an older laboratory method that may miss some types of soluble and fermentable fibre. This means a food with a low crude fibre figure may still contain a reasonable amount of total dietary fibre.

Rather than simply choosing the food with the highest fibre percentage, look at the whole recipe and how your dog responds to it.

How to Add Fibre Safely

Any new fibre-rich food should be introduced gradually.

Suddenly adding a large spoonful of pumpkin, psyllium or vegetables can lead to wind, bloating, discomfort or diarrhoea.

Begin with a small amount and monitor:

• Stool consistency

• Stool frequency

• Gas

• Appetite

• Abdominal discomfort

• Any straining or urgency

Your dog should also have constant access to fresh drinking water.

This is particularly important when using ingredients such as psyllium, which absorb water.

Speak to your vet before making changes if your dog has a diagnosed digestive condition, kidney disease, diabetes, pancreatitis, exocrine pancreatic insufficiency or a history of intestinal obstruction.

The Bottom Line

Fibre can be a really useful part of a dog’s diet.

It can support healthy poos, feed beneficial gut bacteria, help dogs feel fuller and may support natural anal gland emptying.

However, more fibre is not always the answer.

The type of fibre, the amount being fed and the rest of the diet all matter. A supplement cannot compensate for an unsuitable or unbalanced diet, and ongoing digestive or anal gland problems should always be properly investigated.

The aim is not to produce the hardest and smallest poo possible. It is to help your dog pass comfortable, well-formed stools while supporting their wider digestive and nutritional health.

References

1. Donadelli RA et al. Effects of fibre sources on nutrient utilisation and stool quality in dogs. Translational Animal Science. 2019.

2. Fahey GC Jr et al. Dietary fibre sources with differing fermentation characteristics in dogs. Journal of Animal Science. 1990.

3. Leib MS. Treatment of chronic idiopathic large-bowel diarrhoea in dogs with soluble fibre. Journal of Veterinary Internal Medicine. 2000.

4. Alves JC et al. Soluble fibre for the management of chronic large-bowel diarrhoea in working dogs. 2021.

5. Weber M et al. A high-protein, high-fibre diet designed for weight loss improves satiety in dogs. Journal of Veterinary Internal Medicine. 2007.

6. German AJ et al. A high-protein, high-fibre diet improves weight loss in obese dogs. The Veterinary Journal. 2010.

7. Jackson MI et al. Dietary fibre, stool quality and microbial fermentation in healthy dogs and dogs with chronic gastrointestinal disease. Journal of Animal Science. 2019.

8. Salichs M et al. Fibre and probiotic supplementation in dogs with recurrent anal sac impaction. Veterinary Dermatology. 2025.

9. FEDIAF. Carbohydrates and fibre in dog and cat food.