One criticism of the keto diet is that it lacks fiber, but nothing could be further from the truth. There are plenty of high-fiber keto foods that you can include in your diet that help you stay fuller longer, support weight loss, and improve your gut health.
This guide explains why you need fiber on most keto diets and how to get fiber on keto without getting kicked out of ketosis.
High-Fiber, Keto-Friendly Foods
A low-carb diet doesn’t have to be a low-fiber diet. You have lots of options to boost your fiber intake without going over your carbohydrate limit of 50 grams per day. These include low-carb veggies and slow-digesting carbs that won’t affect blood sugar levels or ketosis.
Start with natural fiber sources rich in nutrients like antioxidants and healthy fats over genetically modified options like soluble corn fiber. While that won’t include folate-rich roughage like whole grains or legumes for those on keto, there are so many other options to keep total carbs low.
Try these keto-friendly fiber foods as you meal plan your weekly side dishes, or enjoy them as snacks. All fiber and net carb totals were sourced from the USDA’s FoodData Central.
Fruits (100 gram serving)
- Avocados: Fiber 7g, Net Carbs 2g
- Blackberries: Fiber 5g, Net Carbs 10g
- Blueberries: Fiber 2g, Net Carbs 13g
- Coconut meat: Fiber 9g, Net Carbs 6g
- Raspberries: Fiber 7g, Net Carbs 5g
- Strawberries: Fiber 2g, Net Carbs 6g
Nuts and Seeds (100 gram serving)
- Almonds: Fiber 13g, Net Carbs 9g
- Chia seeds: Fiber 34g, Net Carbs 8g
- Flax seeds: Fiber 27g, Net Carbs 2g
- Hazelnuts: Fiber 10g, Net Carbs 7g
- Pecan nuts: Fiber 10g, Net Carbs 4g
- Pumpkin seeds: Fiber 6g, Net Carbs 9g
- Sunflower seeds: Fiber 9g, Net Carbs 11g
Vegetables (100 gram serving)
- Artichokes: Fiber 5g, Net Carbs 6g
- Bell peppers: Fiber 1g, Net Carbs 4g
- Broccoli: Fiber 2g, Net Carbs 4g
- Brussels sprouts: Fiber 4g, Net Carbs 5g
- Cauliflower: Fiber 2g, Net Carbs 3g
- Cabbage: Fiber 3g, Net Carbs 3g
- Collard greens: Fiber 4g, Net Carbs 1g
- Edamame: Fiber 5g, Net Carbs 4g
- Green beans: Fiber 3g, Net Carbs 3g
- Okra: Fiber 2g, Net Carbs 3g
- Spinach: Fiber 2g, Net Carbs 0g
- Zucchini: Fiber 1g, Net Carbs 3g
Miscellaneous
- Acacia fiber (1 tablespoon): Fiber 5g, Net Carbs 0g
- Psyllium husk (100 grams): Fiber 78g, Net Carbs 11g
If you’re looking for keto-friendly snacks, our Nola Bars and Mallow Munch rice crispy treats include 6g of dietary fiber per serving.
Understanding Fiber’s Role in Keto
Studies support the benefits of dietary fiber on keto. While fiber is known for its role in healthy bowel movements, fiber-rich foods provide a number of additional health benefits for overall wellness:
- Satiety: Getting fiber on keto helps slow down the absorption of fat and delays gastric emptying, which increases feelings of fullness and reduces food intake. (1) This is important for those who are on the keto diet to lose weight.
- Blood sugar control: For people with type 2 diabetes or at risk of developing it, the keto diet is an effective way to lower blood sugar. (2) Fiber isn’t digested and absorbed by the body, making it helpful for keeping your blood sugar within range.
- Constipation relief: Constipation is a common symptom experienced by keto beginners. Insoluble fiber from keto-friendly sources adds bulk to stool to relieve constipation at the start of keto. (3)
- Irritable bowel syndrome (IBS) relief: Studies show soluble fiber is effective in reducing overall IBS symptoms. This may be possible through an increase in anti-inflammatory short-chain fatty acids (SCFAs) when you eat fiber. (4)
- Improved gut health: Those same SCFAs are good for gut lining integrity, your immune system, and reducing inflammation. Daily fiber also feeds beneficial gut bacteria that support your microbiome, which is essential to a healthy metabolism. (5)
- Reduced LDL cholesterol: High levels of low-density lipoprotein — small dense (sd) LDLs in particular — increase your risk of heart disease. Fiber may alter metabolites in gut bacteria that can change the way your body processes cholesterol, lowering LDL. (6)
- Improved heart health: Keto diets often mean an increase in dietary fats. That effect on LDL cholesterol described above helps counterbalance this with improved lipid profiles and, in turn, better cardiovascular health. (7)
- Keto flu relief: At the start of keto, many people experience symptoms like fatigue, headaches, and nausea. Fiber can reduce some of that discomfort by supporting better energy balance and reducing blood sugar swings. (8)
None of this means you should go high-fiber right off the bat. Start slow. Monitor how you feel and adjust from there to avoid unintended side effects like bloating and abdominal discomfort.
Eating excessive amounts of plant foods may also interfere with the absorption of nutrients like calcium and magnesium, due to compounds called anti-nutrients.
Drink plenty of water as you add fiber to your diet. While fiber pulls water into your digestive tract, consuming too much can lead to dehydration, increasing your risk of constipation.
How Much Fiber You Need
The FDA recommends 28 grams of fiber daily as part of a 2,000-calorie diet. (9) Individual needs can vary from there depending on your goals, nutritional needs, and tolerance for fiber. For some, too much fiber leads to excessive bloating, gas, and other gastrointestinal symptoms.
Two types of fiber exist: soluble and insoluble fiber. (10) Soluble fiber easily dissolves in water and forms a viscous, gel-like substance. When it reaches the large intestine, it gets broken down into anti-inflammatory SCFAs such as butyrate, propionate, and acetate.
SCFAs improve gut health by maintaining the integrity of the intestinal barrier and providing protection from inflammation. Keto-friendly sources of soluble fiber include cruciferous vegetables, avocados, flax seeds, sunflower seeds, and hazelnuts.
Insoluble fiber does not dissolve in water. It’s beneficial for those who are experiencing constipation since it increases luminal bulk but may worsen IBS symptoms. Examples of keto-friendly insoluble fiber sources include green beans, okra, spinach, and coconut flour.
If you choose to include more fiber in your keto diet, pay attention to how you feel and then adjust accordingly. If you can’t seem to get the ratio right, talk to a dietitian or your healthcare provider. There could be something else at play.
Keto Made Simple Through Our Keto Kickstart
Most Americans aren’t getting enough fiber. If you’re on a low-carb, high-fat diet like keto, you may be wary of adding too many sources of fiber to avoid affecting ketosis.
Unless you’re following a keto-carnivore approach with minimal to no fiber, you have options for low-carb, high-fiber foods to support better digestive system health and overall wellness.
If you’re ready to start your keto journey, no matter what form it takes, sign up for our Keto Kickstart. It’s a 30-day, step-by-step guide to keto, tracking macros, and meeting your health goals.
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FAQ
Does fiber really cancel carbs?
Fiber doesn’t cancel out carbs, although it’s not digested like other carbs. It’s a good energy source and doesn’t raise your blood sugar; it helps with weight loss, digestive health, cholesterol, and more.
Does fiber kick you out of ketosis?
Unlike other carbohydrates, your body cannot digest fiber, so it won’t kick you out of ketosis or cause your blood glucose levels to rise. As long as you limit yourself to 50 grams of net carbs daily, you should be able to stay in ketosis.
How do I get 30 grams of fiber a day on keto?
To reach 30 grams of fiber on keto, focus on high-fiber, low-carb foods to keep you under 50 grams of net carbs. That could look like an avocado in the morning, a serving of almonds and strawberries in the afternoon, and 2 servings of Brussels sprouts drizzled with olive oil at dinner.
Should I take fiber supplements on keto?
You can take a fiber supplement for keto if you’re not getting a sufficient amount of fiber from your diet, but reading labels is essential. Brands like Metamucil contain psyllium husk, a fiber that doesn’t impact net carbs significantly, but they may contain sugars that disrupt ketosis. Always check the label for ingredients and carb content to ensure they’re compatible with keto. Opt for supplements without added sugars in capsule, gummy, or powder form that you can add to healthy morning smoothies.
How do I stop constipation on keto?
You can relieve constipation symptoms on keto by consuming more insoluble fiber from sources like leafy greens and coconut flour. Stay hydrated as you add more fiber by drinking plenty of water or incorporating potassium-rich electrolytes into your diet.