Fibre on Keto – Its Role and Best Sources

What will you learn from the article?

Fibre plays a vital role in maintaining satiety, preventing constipation, and supporting digestive processes. It also has a positive impact on gut health by nourishing beneficial bacteria, which in turn helps strengthen the immune system.

What is dietary fibre?

Dietary fibre is a form of indigestible polysaccharides and lignins, which are essential for the proper functioning of the digestive system. Fibre is generally divided into two main categories: soluble and insoluble, each offering unique benefits.

Soluble fibre

Soluble fibre includes compounds such as pectins, beta-glucans, and plant gums. These fibres ferment in the large intestine, producing short-chain fatty acids (SCFAs) like acetate, propionate, and butyrate, which have anti-inflammatory effects and help regulate glucose and lipid metabolism. For those on a keto diet, soluble fibre plays an important role in maintaining digestive balance.

What does soluble fibre do?

Soluble fibre forms a gel-like substance in the intestines, which slows down digestion and improves blood sugar control. This type of fibre has been shown to reduce LDL (bad cholesterol) levels by 5-10%, thereby lowering cardiovascular risk—something beneficial on a high-fat keto diet.

Insoluble fibre

Insoluble fibre is found in whole grains, vegetables, and seeds. It acts as a “broom” that sweeps through your digestive tract, reducing the risk of constipation and other gut issues. This is particularly important on a ketogenic diet where fibre from whole grains is typically limited. By incorporating insoluble fibre into your keto meals, you can also reduce the risk of colorectal cancer.

Why is fibre in the keto diet so important?

Getting enough fibre on a keto diet is crucial because the diet restricts many traditional high-fibre foods like grains and some fruits. Maintaining an adequate intake of keto-friendly fibre supports digestion and helps to stabilise blood sugar and insulin levels. Getting fibre on keto also prolongs the feeling of fullness, which is helpful for those aiming for weight loss.

Does fibre affect ketosis?

One of the common questions about fibre on a keto diet is whether it impacts ketosis. The good news is, fibre doesn’t interfere with ketosis because it isn’t metabolised the same way as digestible carbs. In fact, the fermentation of soluble fibre into SCFAs can even aid fat metabolism, supporting ketone production.

Does fibre count as a carbohydrate?

When calculating your daily carb intake, dietary fibre doesn’t count towards your net carbs because it isn’t digested or absorbed. This is why fibre carbs on keto are subtracted from total carbs when calculating net carbohydrates, allowing you to enjoy more keto-friendly fibre sources without affecting ketosis.

How much fibre on the keto diet?

An ideal intake for fibre on a keto diet is about 25-30 grams per day, which aligns with general dietary recommendations. However, it can be tricky to meet this goal on a low-carb diet. Focus on keto fibre sources such as avocados, chia seeds, nuts, and green leafy vegetables, or consider adding fibre supplements like psyllium husks to your routine. Getting enough fibre while on keto will promote gut health and prevent constipation, making your keto journey smoother.

Sources of fibre on a ketogenic diet

Despite the limitations, several fibre-rich foods on keto can help you meet your daily fibre needs while maintaining ketosis. Below are some of the best sources of both soluble and insoluble fibre.

Products rich in soluble fibre

Soluble fibre not only regulates blood sugar levels, which is crucial on a low-carbohydrate diet, but also plays a key role in gut health and lipid metabolism. Below is a list of foods rich in fibre in soluble form.

Avocados

A medium avocado provides about 13-14 grams of fibre, most of which is soluble. They’re also a rich source of healthy fats, helping lower LDL cholesterol.A medium avocado provides about 13-14 grams of fibre, most of which is soluble. They’re also a rich source of healthy fats, helping lower LDL cholesterol.

Chia seeds

With about 10 grams of fibre per 30g serving, chia seeds are a powerful source of soluble fibre and omega-3 fatty acids, both beneficial for heart and digestive health.

Asparagus

A low-carb veggie providing inulin, a prebiotic that supports gut health, asparagus contains about 2 grams of fibre per 100g.

Brussels sprouts

With around 4 grams of fibre per 100g serving, Brussels sprouts are packed with glucosinolates, which may help reduce cancer risk.

Spotted thistle

Known for liver support, spotted thistle seeds are a great source of soluble fibre and offer antioxidant properties.

Products rich in insoluble fibre

Unlike soluble fibre, as the name suggests – insoluble fibre does not dissolve in water, allowing it to mechanically support bowel movements. Here are some key sources of insoluble fibre that are compatible with the ketogenic diet:

Nuts

Almonds provide 12.5 grams of fibre per 100g, most of which is insoluble, supporting regular bowel movements.

Pumpkin seeds and flaxseed

Flaxseeds contain around 27 grams of fibre per 100g, making them excellent for digestive health, while pumpkin seeds provide around 6 grams.

Coconut

Coconut flesh is rich in insoluble fibre – providing around 9g per 100g of product. Coconut is also a source of medium-chain fatty acids (MCTs), which are rapidly metabolised by the liver and can accelerate the production of ketones, helping to maintain ketosis. Regular consumption of coconut can not only support digestive health, but also provide energy in the form of ketones.

Vegetable peels

The peels of vegetables like cucumbers and zucchini offer a natural source of insoluble fibre. Be sure to wash thoroughly to remove any contaminants.

Green leafy vegetables

Spinach and arugula are high in insoluble fibre and rich in vitamins, contributing to overall health and digestion.

Summary

Fibre plays an essential role in keeping your digestive system running smoothly and supporting metabolic health, even on a ketogenic diet. By choosing high-fibre, low-carb foods like avocados, chia seeds, and leafy greens, you can enjoy the benefits of fibre without compromising ketosis. Remember, balancing your fibre intake will help ensure long-term success on your keto journey!

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