How to get 25 grams of fiber a day on keto: An essential guide

November 2, 2025 •

4 min read

According to the American Heart Association, adults on a 2,000-calorie diet should consume around 25 grams of fiber per day, but many people fall short. Achieving this target while restricting carbohydrates on a ketogenic diet may seem difficult, but it is both possible and crucial for digestive health and overall well-being.

Quick Summary

This article outlines practical strategies for incorporating ample dietary fiber into a ketogenic eating plan. It details specific low-carb food sources, compares the benefits of soluble versus insoluble fiber, and provides guidance on supplements to help you consistently reach your 25-gram daily goal. Hydration and lifestyle factors are also covered.

Key Points

Strategic Food Choices: Focus on low-carb, high-fiber foods like avocados, chia seeds, flaxseed, and leafy greens to reach your daily fiber target.
Understand Fiber Types: Incorporate both soluble fiber (for blood sugar control and satiety) and insoluble fiber (for digestive regularity) from keto-friendly sources.
Consider Supplements: Use low-carb fiber supplements like psyllium husk or inulin if whole foods alone are insufficient to meet your 25g goal.
Stay Hydrated: Increasing fiber intake requires drinking plenty of water to prevent constipation and support digestive health effectively.
Portion Control for Nuts: Be mindful of portion sizes for nuts to avoid consuming too many carbs and calories, which can hinder your keto progress.
Plan Your Meals: Integrate fiber-rich foods into each meal and snack to consistently meet your daily requirement without feeling overwhelmed.

Why is fiber so important on a keto diet?

Many people associate high-fiber foods with high-carb foods like whole grains, legumes, and certain fruits. When transitioning to a keto diet, which severely restricts these food groups, a drop in fiber intake can lead to common issues such as constipation. Fiber is a non-digestible carbohydrate that plays a crucial role in digestive health, helping to regulate bowel movements and prevent discomfort. Beyond just regularity, fiber contributes to a healthy gut microbiome, which can positively influence overall health, including mood and immunity. Furthermore, some types of fiber can improve blood sugar control and increase satiety, which are both beneficial for those following a keto lifestyle.

The best keto-friendly food sources for fiber

Sourcing fiber on keto requires focusing on non-starchy vegetables, nuts, and seeds. These options provide a significant amount of fiber while keeping net carb counts low. Here is a list of excellent choices:

Avocado: A versatile fruit, half a large avocado contains about 7 grams of fiber and just 2 grams of net carbs. Add it to salads, make guacamole, or blend it into a keto smoothie for a creamy texture.
Chia Seeds: These tiny seeds are a fiber powerhouse. Two tablespoons can provide an impressive 10 grams of fiber and only 2 grams of net carbs. They can be made into chia pudding or added to shakes and dressings.
Flaxseed: Another excellent seed source, two tablespoons of ground flaxseed offer about 4 grams of fiber and a minimal net carb count of just 0.2 grams. Use it in baking to add structure or sprinkle it on salads and yogurt.
Nuts: Specific nuts are high in fiber and low in net carbs. Pecans offer about 3 grams of fiber per ounce, while macadamia nuts provide 2 grams. Enjoy them in moderation as a satisfying snack.
Green Vegetables: Leafy greens and cruciferous vegetables are staples of a keto diet. A cup of cooked spinach provides about 4 grams of fiber, while a cup of chopped, cooked broccoli contains 5 grams. Other great options include Brussels sprouts, asparagus, and collard greens.
Berries: Small portions of certain berries can be enjoyed on keto. One cup of raspberries or blackberries can contain around 8 grams of fiber, with a manageable net carb count.

Combining foods for fiber-packed keto meals

Achieving your 25-gram fiber goal daily involves more than just eating a list of foods; it's about strategic meal planning. Here’s an example of how you can structure a day:

Breakfast: A keto smoothie with 1/2 an avocado (7g fiber), 2 tablespoons of chia seeds (10g fiber), almond milk, and a scoop of your favorite low-carb protein powder.
Lunch: A large spinach salad (4g fiber) topped with grilled chicken, half a cup of bell peppers (1g fiber), a quarter cup of almonds (4g fiber), and a keto-friendly vinaigrette.
Dinner: Roasted Brussels sprouts (4g fiber) served alongside a fatty cut of meat.

This meal plan easily gets you to or over 25 grams of fiber and demonstrates how simple it can be when you focus on nutrient-dense, high-fiber, low-carb ingredients.

Soluble vs. Insoluble Fiber on Keto

Understanding the two main types of fiber is key to optimizing your digestive health on a ketogenic diet.


Feature	Soluble Fiber	Insoluble Fiber
Mechanism	Dissolves in water to form a gel-like substance in the digestive tract.	Does not dissolve in water and remains mostly intact throughout the digestive system.
Digestive Effect	Slows digestion, which helps control blood sugar and promotes a feeling of fullness.	Adds bulk to stool, helping to speed up the passage of food and waste through the gut.
Keto Sources	Avocados, Brussels sprouts, some seeds, and supplements like psyllium husk.	Leafy greens, nuts, seeds, and the tougher parts of many vegetables.
Best For...	Helping to lower cholesterol and managing blood sugar levels.	Preventing constipation and promoting regularity.

The role of fiber supplements

If you find it challenging to meet your daily fiber target from whole foods alone, supplements can be a helpful tool. The key is choosing products that don't contain added sugars or high-carb ingredients that could disrupt ketosis.

Psyllium Husk: Derived from the husks of Plantago ovata seeds, psyllium is an excellent source of soluble fiber. One tablespoon of powder provides about 8 grams of fiber with less than 1 gram of net carbs, making it a powerful addition to baked goods or mixed with water.
Inulin Powder: Sourced from chicory root, inulin is a soluble prebiotic fiber that feeds beneficial gut bacteria. It's a great option to boost your soluble fiber intake without adding significant net carbs.

Conclusion

Achieving and maintaining a target of 25 grams of fiber a day on keto is entirely feasible with careful food choices. By focusing on nutrient-dense, low-carb sources like avocados, seeds, leafy greens, and nuts, you can support your digestive health and overall wellness without compromising your state of ketosis. Supplements like psyllium husk and inulin can provide extra support when needed. Remember to stay hydrated and listen to your body as you increase your fiber intake to ensure a smooth transition and consistent success. A well-planned ketogenic diet is a high-fiber diet.

A note on moderation

While nuts are a fantastic source of fiber on a keto diet, it is important to remember that portion control is key. Overconsumption can still lead to a higher intake of carbohydrates than intended, especially with nuts like cashews and pistachios. Limiting yourself to a handful can help manage both calorie and carb intake effectively.

Frequently Asked Questions

Yes, some people experience constipation when starting a ketogenic diet, often due to a reduced intake of traditional high-fiber foods. This can be resolved by strategically including keto-friendly, high-fiber foods and drinking enough water.

Chia seeds and psyllium husk are among the most fiber-dense and lowest-net-carb options available on a keto diet. Two tablespoons of chia seeds can provide 10 grams of fiber, while one tablespoon of psyllium husk powder contains 8 grams.

You can easily boost a keto smoothie by adding ingredients like avocado, chia seeds, flaxseed meal, or a scoop of unsweetened psyllium husk powder. These ingredients add fiber without increasing the net carb count significantly.

A supplement is not always necessary but can be helpful if you struggle to consistently reach 25 grams of fiber from whole foods. Look for pure psyllium husk or inulin powder without added sugars.

Excellent high-fiber keto vegetables include avocado, broccoli, Brussels sprouts, spinach, and cauliflower. Cooking these vegetables can sometimes increase their fiber density per cup.

Soluble fiber dissolves in water and helps regulate blood sugar and promote fullness. Insoluble fiber adds bulk and promotes regularity. Keto sources include seeds and avocados for soluble, and leafy greens and nuts for insoluble.

Introducing large amounts of fiber too quickly can cause temporary bloating or gas. It's best to increase your intake gradually and ensure you are drinking plenty of water to give your digestive system time to adjust.