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What’s commonly overlooked in the keto diet? A bit of fiber. This popular diet, where you usually aim for 80% of calories from fat and limit carbs to 20-50g (grams) per day, often faces criticism for its lack in fiber.
This is particularly noticeable in some keto followers. Dana Elia, RDN, an integrative and functional medicine dietitian in Lancaster, Pennsylvania, points out, “A poorly planned keto diet is susceptible to lacking in fiber.” She highlights that dietitians often encounter patients who experience constipation issues when transitioning to the keto lifestyle.
The reality is, a significant number of Americans fall short on the gut-friendly nutrient, as highlighted by the U.S. Department of Agriculture (USDA): Over 90 percent of women and 97 percent of men fail to meet their recommended daily fiber intake. Exclude most carbohydrate sources like whole grains, fruits, and legumes, and the probability of experiencing a deficiency in fiber becomes even higher.
Fiber is crucial for maintaining digestive health. Mayo Clinic explains that since the body doesn’t digest it, fiber moves through the system, promoting regularity by softening and increasing the bulk of stools. Additionally, fiber provides benefits beyond bowel movements; it nourishes the beneficial bacteria in your gastrointestinal tract, supporting healthy digestion and nutrient absorption.
Elia emphasizes, “The digestive tract houses your body’s second brain and is the hub of the majority of your immune system. If you’re on a keto journey, ensuring sufficient fiber intake should be a top priority to maintain a healthy and happy gut,” she suggests. Elia further points out that high-fat diets can slow digestion and reduce GI motility, underscoring the heightened importance of getting an adequate amount of fiber.
Especially for individuals taking specific medications, such as proton pump inhibitors for heartburn, transitioning to a high-fat diet may lead to noticeable changes in digestion, according to Elia.
The 2020–2025 Dietary Guidelines for Americans, as set by the USDA, aim for a daily fiber intake of 28 – 34g (grams), depending on age and gender. Following a keto diet doesn’t make this goal impossible, but it requires consistent effort and determination, notes Keri Glassman, RDN, a practitioner in private practice in New York City. Many high fiber foods have low net carbs (total carbs minus fiber and sugar alcohols, according to Atkins.com) and can keep you in ketosis, the metabolic state that prompts your body to burn fat instead of carbs. Here are 12 options to help you maintain enough fiber intake without jeopardizing your keto goals!
High Fiber Keto Foods
Elia advises, “Every keto enthusiast should include avocados in their diet as they offer an excellent combination of fiber and healthy fats.” According to the USDA, half an avocado contains only 1.4 net carbs but provides an impressive 5g (grams) of fiber.
2. Chia seeds
According to the USDA, a single ounce (oz) of chia seeds provides 9.6g (grams) of fiber (with a net carbs total of 2.2g (grams)). Creating chia seed pudding involves combining the seeds with liquid, resulting in a gel-like substance that pairs well with fruits, natural sweeteners like honey, and a variety of spices. Glassman recommends incorporating chia into small, low-carb smoothies or as a topping for oatmeal, eggs, or salads.
Glassman suggests that nuts are an excellent choice on the keto diet due to their fiber and fat content. Pecans, in particular, stand out as one of the lowest-carb nuts, providing just 1.2 net carbs per ounce (equivalent to 19 halves), according to the USDA. Additionally, this quantity delivers 2.7g (grams) of fiber.
Adding almonds to your keto diet is another wise decision. Recognized as one of the nuts with the highest fiber content, almonds contain 3.5g (grams) (with approximately 2.5g (grams) of net carbs) per ounce (equivalent to 23 whole kernels), according to the USDA.
Glassman recommends these tiny seeds as an excellent crunchy coating for fish or chicken instead of traditional breading. To maximize the absorption of flax’s nutrients, ensure they are ground — this way, you can enjoy the heart-healthy and cholesterol-lowering advantages of flaxseed’s high omega-3 fatty acid content, as suggested by Mayo Clinic. According to the USDA, 1 tablespoon (tbsp) of ground flax contains 2g (grams) of fiber and zero net carbs. Essentially, it’s a nutritional freebie. Enjoy!
6. Collard Greens
While starchy vegetables like sweet potatoes are typically avoided on the keto diet, there are abundant options among keto-friendly greens. Elia suggests focusing on high-fiber choices like collards. Choose cooked greens over raw ones, as they condense during cooking, allowing you to consume more fiber per cup. According to the USDA, one cup of cooked collards contains approximately 2g (grams) of net carbs and 5.6g (grams) of fiber.
Cauliflower is becoming more popular, and this is fantastic news for those following the keto diet. According to the USDA, a one-cup serving of this low-carb vegetable contains just about 3g (grams) of net carbs and 2g (grams) of fiber. Furthermore, its versatility shines through as it can be utilized to create a cauliflower pizza crust, chopped finely as a rice substitute, mashed as a replacement for mashed potatoes, and blended into creamy soups.
8. Pumpkin Seeds
According to the USDA, an ounce of dried pumpkin seed kernels provides slightly over 1g (gram) of net carbs and 1.7g (grams) of fiber. Additionally, they are conveniently enjoyed as a handful snack, allowing you to effortlessly add a bit more fiber into your daily diet.
According to the USDA, a small piece of coconut meat (approximately two inches by two inches) provides around 3g (grams) of net carbs and 4g (grams) of fiber. According to Elia, it also serves a dual purpose by aiding in increasing fat intake. You can find this in the frozen section of certain grocery stores. If it’s not available in your area, go for unsweetened shredded coconut.
Adding fruit into a keto diet can be challenging, but raspberries stand out as a favorable option due to their high fiber content. According to the USDA, half a cup of fresh raspberries provides 4g (grams) of fiber and 3.3g (grams) of net carbs. Give frozen raspberries a try by simmering them down to create a syrupy topping for your keto pancakes.
Artichokes present a surprisingly effective choice for increasing the fiber content in your keto diet. According to the USDA, a single canned artichoke heart provides 1.7g (grams) of fiber and less than 1.9g (grams) of net carbs. Adding them as a topping on a keto pizza, roast or grill fresh artichokes, or bake them with keto-friendly cheese for a delightful appetizer.
Fermented foods, rich in probiotics, contribute to gut health, burst with flavor, and are low in carbs. According to the USDA, half a cup of sauerkraut provides 2g (grams) of fiber and just over 1g (gram) of net carbs. Additionally, you can use it to infuse a tangy flavor boost into various dishes, whether it’s meat cuts or salads.
Prioritizing fiber in your diet is crucial, regardless of your chosen eating plan. If you’re starting the keto journey, the wisest and safest approach is to seek guidance from a registered dietitian well-versed in the do’s and dont’s of this diet. They can create a personalized plan to make sure that your nutritional needs are met, as emphasized by Elia.
Constipation, according to the NIH is having fewer than three bowel movements per week or experiencing hard, dry stools that are difficult to pass. If attempts to increase your fiber intake, increase water consumption, and engagement in regular physical activity do not show positive results in relieving constipation, it is highly recommended to consult with your doctor for further guidance.