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Ferment on This: Dietary Fibre for Your Pets

By Dr. Hannah Godfrey, PhD · February 10, 2022 · Updated January 2, 2026

What is Dietary Fibre?

Dietary fibre is a type of plant-derived carbohydrate . Carbohydrates can be broken down into simple versus complex. Simple carbohydrates would include sugars like glucose. However, dietary fibre is a complex carbohydrate consisting of many simple sugars in different configurations.

The dietary fibres are indigestible , meaning that your pet cannot break them down and digest them. The most common classification for dietary fibre is solubility: soluble fibres and insoluble fibres . However, they can also be classified by viscosity and fermentability.

Viscous fibres will thicken in water to create a gel-like substance, whereas non-viscous fibres will not. Fermentable fibres are metabolized by microbes in the digestive system and provide an energy source.

However, the digestive system cannot metabolize non-fermentable fibres. The non-fermentable fibres are considered bulking agents! It may seem counter-intuitive, but even though fibre cannot be broken down and digested, they can still provide many benefits for both us and our pets!

Health Benefits of Dietary Fibre

In humans, dietary fibre has been heavily studied for its many health benefits. Recent research shows that these benefits appear to be similar in our pets. Don't just take our word for it - Dr. Joe Inglis, BVSc, MRCVS, a UK-based Veterinarian, expert in animal nutrition, founder of VetChef and collaborator on the Tom&Sawyer VetChef line of recipes (found at www.vetchef.pet) speaks to the importance of dietary fibre for pets:

"Incorporating dietary fibre into a pet's diet is fundamental for promoting optimal digestive health. Fibre plays a crucial role in modulating gastrointestinal function, enhancing the gut microbiome's balance, and contributing to overall well-being. This nutrient not only aids in digestion but also has significant implications for preventing obesity and managing metabolic disorders. As such, ensuring adequate fiber intake can be transformative for our companion animals." - Dr. Joe Inglis , BVSc, MRCVS.

Dietary fibre may have benefits for preventing obesity, diabetes, and cancers and aiding in healthy digestion and gut health , weight loss, lowering blood pressure, and maintaining blood sugar levels.

Gut Health Benefits of Fibre:

Fibre helps to maintain a healthy gut, specifically fermentable fibres. It promotes a healthy gut microbiome by acting as a food source for the microbiota. These beneficial microbes ferment the fibre, producing short-chain fatty acids . The “good” bacteria benefits while the growth of the“bad” bacteria is prevented.

Fibre can also affect gastric emptying by slowing it down . This means that food will leave the stomach at a slower rate, increasing the amount of time food is in the gastrointestinal tract. These factors can help your pet feel full for longer and provide digestive enzymes more time to properly digest the food, all of which may also reduce the bulk of your pet’s poop and frequency!

Crude Fiber vs Total Dietary Fiber

When you look at the label on your pet’s food, you’ll see that Crude Fibre is included in the nutrient analysis. What does this tell you about the fibre content of the diet?

Honestly, not much! Crude fibre accounts for only the insoluble fibres, namely cellulose and lignin.

Total dietary fibre accounts for both the soluble and insoluble fibres and is often considered more valuable when evaluating the fibre content of a pet food diet.

Currently, AAFCO only requires that pet food labels state the crude fibre content. However, there is a push from the industry and research community to change this to include total dietary fibre.

Sources of fibre in pet foods

Fibre is an important component, and it is one (of many) reasons to include plant sources in our pet’s diets.

Both soluble and insoluble fibres are important:

Good sources of soluble fibre can consist of:

Oats

Sweet Potatoes

Broccoli

Carrots

Apples

For insoluble fibres , good sources can include:

Brown rice

Quinoa

Amaranth

Potatoes

Tomatoes

If you have any questions about your pet’s diet, Tom&Sawyer meals, or dietary fibre, connect with our in-house animal nutritionist, Hannah Godfrey, at hannah@tomandsawyer.com.

Written by: Hannah Godfrey Animal Nutritionist BSc.H. | MSc. | Ph.D. www.tomandsawyer.com

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About the author

Dr. Hannah Godfrey, PhD

Animal Nutritionist · Lead Nutrition Scientist & Technical Advisor

Hannah leads the nutrition science behind every Tom&Sawyer recipe — a PhD animal nutritionist who turns peer-reviewed nutrition into meals portioned to each pet's real needs.

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