Ketogenic diet comes with a ton of controversy and accusations.
Due to their low-carb high-fat nature, journalists and even medical professionals often point a finger toward the lack of fiber in these types of diets.
Portrayed by the media as being a bacon-and-egg diet with greasy cheeseburgers and lots of fatty steak and pork rinds on the side, it’s often difficult to get to the truth that these journalists and medical professionals ignore:
Yes, ketogenic means the diet is high in fat, so you’ll eat an adequate amount of protein foods every day, but ketogenic diets are also packed with salads and vegetables.
They are not zero carb unless you’re extremely insulin resistant.
Non-starchy vegetables, nuts, seeds, legumes, and low-glycemic fruits — all very common on low-carb diets — contain a wealth of healthy dietary fiber.
You don’t have to worry about having to give up the whole wheat bread and brown rice.
In fact, low-carb breads contain more fiber than the breads they replace!
There’s no good reason to believe that low-carb diets are dangerously low in fiber. This is simply a misunderstanding of what people on low-carb diets actually eat.
In this post, I’m going to explain what fiber is, reveal fiber’s benefits, and then share why dietary fiber is so important for those on Keto.
You also get a list of the best high-fiber low-carb foods that can help ensure that you’re getting an adequate amount of fiber in your ketogenic diet without having to actually count those grams.
What is Dietary Fiber?
Dietary fiber consists of non-starchy polysaccharides, some of which include:
- resistant starch
- resistant dextrin (corn sugar)
Fiber is the portion of a plant that you do not digest and is often referred to as roughage. Most of it passes through the body still intact.
Dietary fiber is classified as a carbohydrate and comes in two types:
- Soluble fiber
- Insoluble fiber
Soluble fiber easily dissolves in liquid, turning into a sticky, gel-like substance, while insoluble fiber doesn’t gel, but soaks up liquid instead, creating bulk and ease of movement.
Once fiber hits the colon, the large intestine, soluble fiber is fermented by bacteria and used to nourish the large intestinal lining.
This is usually accomplished from resistant starches, called “resistant” because they resist being digested.
Insoluble fiber may, or may not, ferment, depending on the body’s needs at the time. However, insoluble fiber adds bulk, absorbs toxins from food, and lowers the production of bacterial toxins in the digestive tract.
Bacteria in the colon, however, can break down resistant starches and will turn the starches into fatty acids that can feed the microbiota of the large intestine.
The transformation of resistant starch to fatty acid means that calories are being produced and used from this reaction, but the count is fairly small since you only need about 25 to 35 grams of fiber per day, depending on your gender and your age.
According to the Institute of Medicine (IOM), dietary reference intake for men between the ages of 14 and 50 is 38 grams.
For women between 19 and 50, dietary intake only needs to be 25 grams. However, this is based on an average calorie intake for these individuals, which means that as you get older, you’ll need less fiber.
A better rule of thumb is to consume about 14 grams of fiber for every 1,000 calories per day that you take in.
For the average low carber who eats about 1,500 calories per day, this would be a minimum of 21 to 25 grams of fiber, with maintenance being more than that.
The Institute of Medicine calls this the nutrient-dense approach and is their recommendation for all age groups.
Colette Heimowitz over at the Atkins website recommends you spread out your fiber intake across your meals and snacks to make it easier to get in the recommended daily amount.
Twenty-five to 35 grams of fiber per day spread out over three meals would be about 7 to 10 grams of fiber per meal, and a little bit less than that if you eat something with fiber for a snack.
Taking supplements, such as psyllium husks, would cut back on the amount of fiber you’d need to eat at each meal or snack, but supplements won’t be as nutritious as eating plenty of fresh produce would be, so this is more suitable for those who must stay very low in carbs to see results.
Both types of fiber are found in plant foods, so on Keto, you don’t have to pay attention to which type of fiber you’re eating at any given time.
While Dr. Atkins recommended that you try to balance your intake of fibers, you can just eat a wide variety of non-starchy vegetables, nuts, and seeds to get the proper amount of each type of fiber.
Benefits of Fiber?
Soluble fiber binds to cholesterol molecules in the stomach and upper intestine, ushering them through the digestive process before they have a chance to be absorbed into the bloodstream.
Soluble fiber also slows down transit time, which can help to improve blood glucose control.
This is why those with diabetes, cholesterol problems, or metabolic syndrome are advised to keep their fiber intake high.
Fiber will keep you feeling full, so you eat less at meals and snacks, but it will also improve your blood sugar and insulin curve after meals.
Insoluble fiber resists digestion, so it too, travels through the digestive process unharmed. Some forms, such as resistant starches, can be fermented in the colon, often referred to as pre-biotics, rather than probiotics.
A pre-biotic feeds the bacteria in your large intestine while a probiotic is the bacteria itself.
Side Effects of Fibers
Fiber has no effect on your blood glucose level, so it won’t raise your basal insulin level either. Nor will it give you blood sugar spikes after meals.
Since it doesn’t affect blood sugar, most low-carb programs allow you to subtract the amount of fiber in your food from its total carbohydrate count, but not all Keto diets do.
Dr. Phinney and some of Dr. Atkins’ earlier low-carb diets use total carb counts instead of net. This is because fiber still supplies calories, even though a food’s “net” carb count is super low.
Fiber’s long-term satiety effect also gives a boost to your weight loss efforts because it makes it easier to eat at a calorie deficit.
But if you were not eating a lot of produce before you started your ketogenic diet, the amount of fiber you’ll get on keto might give you a stomach ache or cause other uncomfortable side effects, such as bloating and gas.
If you were not already consuming the 5 servings of produce recommended for a well-balanced diet, before going keto, you’ll want to add fiber foods to your diet very slowly.
Also, make sure that you drink plenty of water.
Since insoluble fibers absorb liquids to create quite a bit of bulk, you’ll need to drink plenty of water to avoid constipation on Keto.
Why Dietary Fiber on Keto?
The body doesn’t absorb dietary fiber, so you might be wondering why the unused portion of your food is even important, especially since Keto is focused on obtaining better health.
While fiber is not an essential nutrient, Dr. Atkins believed it cleanses the digestive tract, enhances its function, and thereby, helps most if not all digestive ailments.
In Dr. Atkins’ Vita-Nutrient Solution, on page 224, he stated:
“Metabolized by intestinal bacteria into substances that prevent colon cancer, fiber also dilutes and speeds the removal of carcinogens and other toxins in food so that they spare the delicate lining of the GI tract. It also helps achieve optimal blood sugar control and cholesterol levels by slowing digestion and maximizing cholesterol excretion.”
Fiber is an integral part of a healthy diet.
It plays an important role in helping to maintain a healthy digestive system.
However, modern-day manufacturers have drastically increased the refining of food to the point where fiber is seriously lacking in the standard American diet.
Sugar isn’t the only item that Dr. Atkins blamed for the rise in digestive problems, appendicitis, hernia, hemorrhoids, and constipation.
He also believed that a lack of fiber increased your risk for:
- colorectal cancer
- breast cancer
Since low-fiber foods provide less satiety, it’s easy to overeat all of those refined carbs.
On keto, refined carbs are not a problem, but many dieters still have problems understanding what returning to a whole foods diet even means.
Throughout Dr. Atkins low-carb career, he always recommended a ketogenic diet for his overweight patients that was also high in fiber.
Zero carbs or very low-carb diets were only used for those who couldn’t tolerate a high-fiber diet.
For patients who had a low-carbohydrate tolerance, he always recommended lots of:
- leafy green vegetables
- psyllium husks
- wheat bran
- oat bran
- guar gum
- apple pectin
A well-constructed Keto Diet emphasizes lots of vegetables and low-glycemic fruits, as well.
In addition, fiber’s characteristic of absorbing liquids keeps you feeling full for much longer than highly refined processed foods do, so getting plenty of fiber will also make dieting more comfortable.
High Fiber Low Carb Foods
There is no fiber in meat, fish, poultry, eggs, dairy products, and healthy fats, but you’ll find plenty in:
You’ll also find plenty of fiber in most low-carb:
- whole-grain tortillas
- baking mixes
- flours or blends
However, many find that low-carb products cause them to stall, so it’s best to introduce them one at a time, so you can watch how your body reacts to each product.
Here are the BEST high-fiber low-carb foods for the Keto Diet:
1. Organic Black Soy Beans
If you don’t like traditional soy beans, you’ll be pleasantly surprised to discover that canned black soy beans taste very much like traditional black beans.
Try tossing them into your next batch of low-carb chili and no one will even know that they are low carb.
Black soybeans are a rich source of fiber.
One cup of beans is 16 carbs, but 14 of those carbs are fiber, so they will only cost you 2 net carbs per cup.
2. Carbquick Baking Mix
Carbquick is a low-carb product that is similar to a commercial Bisquick, but is made with palm oil shortening.
This baking mix enables you to enjoy biscuits, pancakes, and waffles while doing keto.
Carb count for a 1/3 cup serving is 16 carbs, but 14 of those carbs are fiber. This comes to only 2 net carbs per serving.
Avocados are loaded with healthy mono saturated fats.
An average sized avocado will cost you about 15 carbs, but 12 of those carbs are pure fiber. This means an entire avocado is only 3 net carbs.
Diced up in your salad or smashed to make guacamole, avocados are rich in antioxidants, as well as fiber.
A whole globe of artichoke is 14 carbs, but 10 of those carbs will give you a satisfying amount of fiber.
This comes to only 4 net carbs for the whole thing!
Dipped in mayonnaise or melted butter, the leaves are tender and succulent. Just don’t try to eat the spines.
5. Collard Greens
Green leafy vegetables are fiber windfalls and collard greens are no exception.
A cup of cooked greens is 11 carbs, but 8 of those carbs are fiber.
This comes to only 3 net carbs.
If you’ve never tried a blackberry, you’re really missing out.
Blackberries are high in antioxidants, just like avocados, and come with plenty of Vitamin C.
One cup of blackberries is 14 carbs, but 8 of those carbs are fiber.
This comes to 6 net carbs per cup of berries.
Try serving them with a dollop of whipped cream on top.
These are dark or golden seeds that have been ground into flour.
They are almost total fiber.
One-quarter cup of meal, what you would use to make a One Minute Muffin is 8 carbs, but 6 of those carbs are fiber! This makes a quarter cup serving only 2 net carbs.
8. Mission Carb Balance Tortillas
Mission now puts out a couple of different types of low-carb tortillas.
The original tortilla is soft and pliable like a real tortilla, but is packed with fiber.
Carb count for one tortilla is 19 carbs, but 13 are fiber, so they are 6 net carbs each.
Smaller fajita-sized tortillas are made with whole wheat and come in at 13 carbs with 9 grams of fiber. They are only 4 carbs each.
9. Chia Seeds
These are small black seeds that come from the Salvia hispanica plant.
They swell and turn into a gel when mixed with liquids. Many low-carb dieters enjoy chia seed pudding as a snack or finale to their low-carb meal.
One tablespoon is about an ounce of seeds and costs you 5 carbs, but all 5 of those carbs are fiber.
This makes chia seeds one of the best low-carb foods you can eat.
Along with fiber, you’ll also get a healthy dose of omega 3 fatty acids, which fights inflammation in the body and lowers your risk for heart disease.
Like collard greens, asparagus is quite high in fiber. One cup of sliced stalks are 8 carbs, with 4 grams of fiber, so you get 4 net carbs per cup.
11. Red Raspberries
One cup of red raspberries are chock full of antioxidants and make a nice summer treat on keto.
At 8 carbs per cup, 4 of those carbs are fiber, so they will only cost you 4 net carbs. These berries are very fragile and add a tasty addition to your summer salads or a gelatin salad.
Strawberries are a bit higher in carbs than other berries are, but the fiber boost is significant.
One cup of sliced strawberries weighs in at 14 carbs, but 4 carbs are fiber, so they are 10 net carbs.
13. Brussels Sprouts
Brussels sprouts are like little cabbages that are easily cooked in the microwave.
They run about a carb a piece, for the medium-sized sprout, so 1 cup of spouts is about 12 carbs.
Four of those carbs are fiber, leaving you with a net carb count of 8.
Like many other vegetables, brussels sprouts contain more Vitamin C than oranges.
14. Green Beans
Easily available fresh, frozen, or canned, green beans are also a bit higher in carbs.
A cup of beans comes to 10 carbs, but 4 of those carbs are fiber, leaving you with 6 net carbs per cup.
Spinach is going to shrink quite a bit when you cook it, so Atkins recommends that you measure the spinach in its raw condition first.
For a full cup of cooked spinach, you’ll need 6 cups of raw leaves.
Those leaves are 7 carbs, but 4 of them are fiber, so a full cup of cooked spinach is only 3 net carbs.
All nuts have a significant amount of fiber, but almonds have twice the fiber that macadamia nuts do and 25 percent more than walnuts.
They do come with a high calorie count, so the serving size is quite small.
A quarter cup of almonds is about 1 ounce and has 6 carbs with 4 of those carbs being fiber. That makes the net count for almonds only 2 carbs.
Broccoli is an extremely popular low-carb vegetable due to its versatility and high Vitamin C content.
Great in soups, casseroles, or steamed, an average sized stalk, about 1-1/2 cups of florets, is 10 carbs with 4 of those carbs fiber.
This comes to only 4 net carbs.
Cauliflower is the most popular low-carb vegetable due to its bland flavor.
This makes it a good substitute for potatoes and adds bulk to casseroles, soups, and stir-fries.
One cup is 6 carbs, but 4 of those carbs are fiber, so it weighs in at only 2 net carbs.
19. Coconut Flour
Coconut flour doesn’t cook up like other low-carb flour alternatives because it soaks up a lot of liquid.
This means a little bit of flour goes a long way.
One tablespoon is 5 carbs, but 3-1/2 of those carbs are fiber, so the net carb count comes to 2.5 net carbs per tablespoon.
20. Finely Ground Almond Flour
A popular ingredient in low-carb baking, a quarter cup of finely ground almond flour is 5 carbs, but 3 of those carbs are fiber.
This makes one serving only 2 net carbs.
This can be used to replace graham crackers crumbs for low-carb pies and is great for muffins, pancakes, and quick breads.
Discovering low-carb high fiber foods can appear to be a challenge at first, but almost all non-starchy vegetables, low-glycemic fruits, and even peanut butter contain some amount of both types of fiber.
This is why a nutrient-dense ketogenic diet is heavy on vegetables and low in refined starches and sugars.
Overall, low-carb diets are not low in fiber unless you don’t enjoy salads and vegetables or you need to keep your carbs ultra-low. Even then, it’s still possible to use supplements or high-fiber whole foods like flaxmeal, chia seeds, and psyllium husks to get the fiber you need for optimum health.
Fiber does not raise blood glucose or insulin, which makes it compatible with the goals of Keto, especially since it contributes to satiety and helps to keep you feeling full for longer than non-fibrous foods do.
Getting plenty of fiber makes it easier to stick to your low-carb diet.