One thing that’s often missing from the keto diet? A little bit of roughage. The popular diet, which typically requires you to get up to 80 percent of your calories from fat and only 20 to 50 grams (g) of carbohydrates per day, is often criticized for its lack of fiber.
And that’s certainly true in the case of some of its followers. “A poorly planned keto diet is at risk of being deficient in fiber,” says Dana Elia, RDN, an integrative and functional medicine dietitian in Lancaster, Pennsylvania. She notes that dietitians frequently see patients who complain of constipation when they go keto.
Thing is, most Americans don’t get enough of the GI-friendly nutrient anyway, according to the U.S. Department of Agriculture (USDA): More than 90 percent of women and 97 percent of men don’t meet their recommended daily amount of fiber. Rule out most sources of carbohydrates, including whole grains, fruits, and legumes, and it’s even more likely you’ll be fiber deficient.
Fiber plays a key role in digestive health. Because it’s not digested by your body, it passes through your system and keeps you regular by softening and adding bulk to your stools, per Mayo Clinic. And it has benefits beyond bowel movements: It feeds the good bacteria in your GI tract, aiding healthy digestion and nutrient absorption.
“The digestive tract is where your body’s second brain is, and it’s home to the majority of your immune system,” says Elia. “If you’re following keto, it should be one of your biggest priorities to make sure you get adequate fiber to keep your gut healthy and happy,” she adds. And, she notes, high-fat diets slow digestion and decrease GI motility, so it’s especially important to get enough.
Particularly if you’re on certain drugs, like proton pump inhibitors for heartburn, you may notice changes in your digestion if you transition to a high-fat diet, says Elia.
The USDA’s 2020–2025 Dietary Guidelines for Americans set a goal of 28 to 34 g of fiber a day, depending on age and sex. Following a keto diet food list doesn’t mean it’s impossible to get what you need, but you have to remain diligent and determined to make it happen, says Keri Glassman, RDN, who is in private practice in New York City. Many fiber-rich foods contain few net carbs — that is, total carbs minus fiber and sugar alcohols, per Atkins.com — and will keep you in ketosis, which is the metabolic state that causes your body to burn fat instead of carbs. Here are 12 to help keep your fiber intake up without derailing your keto goals!
Avocado
“All keto followers should consume avocados, because they’re a great source of fiber and fat,” says Elia. Half an avocado contains just 1.4 net carbs, but a whopping 5 g of fiber, per the USDA.
Chia Seeds
One ounce (oz) of chia seeds offers 9.6 g of fiber (and a net carbs total of 2.2 g), per the USDA. You can make chia seed pudding by mixing the seeds with liquid, creating a gel-like substance that you can enjoy mixed with fruits, natural sweeteners like honey, and your choice of spices. Glassman suggests sprinkling chia into small, low-carb smoothies or onto oatmeal, eggs, or a salad.
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Pecans
Nuts can be a great option on the keto diet because of their fiber and fat, says Glassman. Pecans are one of the lowest-carb nuts, offering just 1.2 net carb per oz (19 halves), notes the USDA. That amount will also supply 2.7 g of fiber.
Flaxseed
These small seeds make a killer crunchy coating for fish or chicken in lieu of breading, says Glassman. So you can better absorb the nutrients in flax, make sure they’re ground — you'll reap the heart-healthy, cholesterol-lowering benefits of flaxseed’s high omega-3 fatty acid content, says Mayo Clinic. The USDA reports that 1 tablespoon (tbsp) of ground flax boasts 2 g fiber and 0 net carbs. Basically, a freebie — eat up.
Collard Greens
Starchy veggies like sweet potatoes are notoriously off-limits on keto, but there are plenty of keto-friendly greens. Target high-fiber picks like collards, says Elia. They cook down nicely, so go for cooked rather than raw greens to get in more fiber per cup. One cup of cooked collards has about 2 g of net carbs and 5.6 g of fiber, per the USDA.
Cauliflower
Cauliflower is having a moment — and that’s great news for keto diet followers. A 1 cup serving of this low-carb veggie has only about 3 g of net carbs and 2 g of fiber, notes the USDA. Plus, it’s super versatile: It can be used to make cauliflower pizza crust, chopped small to stand in for rice, mashed to replace mashed potatoes, and blended into creamy soups.
Pumpkin Seeds
An ounce of dried pumpkin seed kernels yields a little more than 1 g of net carbs and 1.7 g of fiber, per the USDA. Plus, they’re simple to grab as a handful for a snack, so you can sneak a bit more fiber into your day. These recipes can help you get started.
Coconut
A small piece of coconut meat (about two inches by two inches) offers about 3 g of net carbs and 4 g of fiber, per the USDA. “Plus, it goes double duty to help you get more fat,” says Elia. Look for this in the frozen section at some grocery stores. If you can’t find it near you, go for unsweetened shredded coconut.
Raspberries
It can be tough to figure out how to fit fruit into a keto diet, but raspberries are a particularly good choice because of their fiber content. A half cup of fresh raspberries offers 4 g of fiber and 3.3 g of net carbs, the USDA notes. Consider cooking down frozen raspberries and using them as a syrupy topping on keto pancakes.
Artichokes
Artichokes are a surprisingly good option for getting more fiber into your keto diet. One canned artichoke heart offers 1.7 g of fiber and less than 1.9 g of net carbs. Add them as a topping to a keto pizza, roast or grill fresh artichokes, or bake with keto-friendly cheese as an appetizer.
Sauerkraut
Fermented foods — packed with probiotics — are good for your gut, full of flavor, and low in carbohydrates. A half cup of sauerkraut supplies 2 g of fiber and a little more than 1 g of net carbs, per the USDA. Plus, you can use it to add a tangy flavor boost to whatever you’re eating, from cuts of meat to salads.
Bonus: Green Smoothies
Many of the above foods can be added to a fiber-packed smoothie, says Glassman. Tossing in frozen spinach, zucchini, or cauliflower (like cauliflower rice) adds fiber, vitamins, and minerals for a respectable amount of carbs.
While zucchini or cauliflower may seem like strange smoothie additions, they impart a creamy texture without a strong vegetable taste. Chia seeds are also great in smoothies!
Just go easy on the size of the smoothie, to be sure not to kick yourself out of ketosis.
One Last Note About Fiber on the Keto Diet
Fiber is important for everyone, regardless of your eating plan. If you’re going keto, your best — and safest — course of action is to enlist a registered dietitian knowledgeable in the diet to design a plan that will meet your nutrient needs, says Elia.
Constipation is defined as fewer than three bowel movements a week, or stools that are hard and dry or difficult to pass, per the NIH. If increasing your fiber intake, drinking more water, and being physically active don’t help move things along, talk to your doctor.
Kayli Anderson, RDN
Medical Reviewer
Kayli Anderson has over a decade of experience in nutrition, culinary education, and lifestyle medicine. She believes that eating well should be simple, pleasurable, and sustainable. Anderson has worked with clients from all walks of life, but she currently specializes in nutrition therapy and lifestyle medicine for women. She’s the founder of PlantBasedMavens.com, a hub for women to get evidence-based, practical, and woman-centered guidance on nutrition and cooking, hormone health, fertility, pregnancy, movement, mental well-being, nontoxic living, and more.
Anderson is board-certified in lifestyle medicine and serves as lead faculty of the American College of Lifestyle Medicine’s (ACLM) "Food as Medicine" course. She is past chair of the ACLM's registered dietitian member interest group, secretary of the women's health member interest group, and nutrition faculty for many of ACLM's other course offerings. She is the coauthor of the Plant-Based Nutrition Quick Start Guide and works with many of the leading organizations in nutrition and lifestyle medicine to develop nutrition content, recipes, and educational programs.
Anderson frequently speaks on the topics of women’s health and plant-based nutrition and has coauthored two lifestyle medicine textbooks, including the first one on women’s health, Improving Women's Health Across the Lifespan.
She received a master's degree in nutrition and physical performance and is certified as an exercise physiologist and intuitive eating counselor. She's a student of herbal medicine and women's integrative and functional medicine. She lives with her husband in the Colorado Rocky Mountains, where you’ll find her out on a trail or in her garden.
Jessica Migala
Author
Jessica Migala is a freelance writer with over 15 years of experience, specializing in health, nutrition, fitness, and beauty. She has written extensively about vision care, diabetes, dermatology, gastrointestinal health, cardiovascular health, cancer, pregnancy, and gynecology. She was previously an assistant editor at Prevention where she wrote monthly science-based beauty news items and feature stories.
She has contributed to more than 40 print and digital publications, including Cosmopolitan, O:The Oprah Magazine, Real Simple, Woman’s Day, Women’s Health, Fitness, Family Circle, Health, Prevention, Self, VICE, and more. Migala lives in the Chicago suburbs with her husband, two young boys, rescue beagle, and 15 fish. When not reporting, she likes running, bike rides, and a glass of wine (in moderation, of course).