What is fiber? Fiber is a carbohydrate that cannot be digested by our bodies. When you eat something that's high in carbs, it's converted to glucose in your body which causes an insulin response. But fiber cannot be converted to glucose and instead passes through your body undigested. Therefore, fiber doesn't create an insulin response and doesn't raise the glucose levels in your blood like other carbs do. When you hear people talk about 'net carbs' this is why. When you look at the carb count of any given food, you can subtract the fiber from the total carbs because they are not digested like other carbs. Because of this, fiber can reduce the insulin-stimulating effects of carbs and can help prevent obesity.
There are two types of fiber to consider as well - soluble and insoluble, based on whether or not it can be dissolved in water. You'll see a list of keto-friendly high fiber foods below. Avocado and berries are a good source of soluble fiber and leafy vegetables and nuts are a good source of insoluble fiber. Soluble fiber will reduce carbohydrate absorption so it is helpful in order to reduce blood glucose and insulin levels.
Natural foods can contain a lot of fiber but when foods are heavily processed much of the fiber is removed. This is just one reason (out of many!) that we want to avoid heavily processed food and stick to food that is as whole and as natural as possible. We'll get a good balance of macros when we do this - including adding natural fiber to your diet. If we're eating highly processed foods, we're eating foods that have more than likely had most of the fiber stripped away and that leaves the bad part of the food remaining and takes the good part away that our bodies need to help aid in digestion. Orange juice is a good example of this. When you eat an orange you're getting all the fiber and nutrients of the orange but if you're buying a jug of orange juice at the grocery store you're essentially buying a jug of candy. When the oranges are processed and made into just the juice, it's stripped of many of the nutrients within the orange and you're left with the empty carbs, creating just a glass of orange flavored sugar liquid. How easy is it to drink an entire glass of orange juice? Pretty easy. It takes about 4-5 oranges minimum to make a glass of orange juice - could you eat 4-5 oranges in the time you drink that glass of juice? Probably not. And your body would tell you to stop - it's too much. But when we drink the glass of juice it's easy to overconsume and get too much of the carbs.
According to Rami & Vicky Abrams in Keto for Dummies, there are four primary benefits of fiber:
- It slows the rate at which sugar is absorbed in the bloodstream
- It moves through your intestines more quickly than other foods
- It physically cleans your colon
- It keeps you regular
In addition to those four, studies have shown that you can reduce your risk of obesity and type 2 diabetes simply by having enough fiber in your diet and eating foods that are whole foods and unprocessed. If you're buying something in a box on the grocery store shelf that has an expiration date that's far out - you're buying processed food and that's not going to give you health benefits.
Eating healthy foods that are high in fiber can also help your microbiome - your gut health. You need certain bacteria in your gut and by following the Standard American Diet we've messed up that balance. This is why we see so many ads for prebiotics and probiotics - we're trying to correct the problem we've created. But eating high fiber foods can help correct this and get your gut healthy again.
If you're looking for ways to add quality fiber to your diet you can add these foods.
Vegetables that are high in fiber:
- Bell peppers
- Brussels sprouts
- Green beans
You can also find keto-friendly fruits that are high in fiber:
So when you're planning your meals and shopping at the grocery store, plan around foods on this list. Incorporate plenty of fiber and stay away from the processed foods that have stripped out the essential nutrients we need.