If you’re like most Americans, you likely consume less than 14 grams of fiber per day, falling very short of the 25 grams per day recommended for women and the 38 grams per day recommended for men. If you missed it, that means most of us are getting less than half of what we need! Fiber isn’t just a powder your grandparents use to “keep them regular.” Fiber plays a vital role in our digestive and overall health. We know it helps prevent constipation and we’re fairly certain it protects against colon cancer. We’re pretty darn sure it helps prevent diabetes and heart disease as well, although the evidence isn’t quite as clear.
This wouldn’t be so important if the majority of us weren’t grossly under-eating fiber and if heart disease, diabetes, and colon cancer weren’t major health issues. These are also health issues that are often silent, meaning you don’t realize it’s going on until you’re sick or diagnosed with a screening at which point some damage may have already been done. The choices we make about our diet and health in our 20’s, 30’s, and 40’s have a huge impact on our health later in life, so this is something we need to pay attention to now!
I feel strongly that when you know how and why something works, you’re more likely to be on board. So let’s take a look at what fiber actually is and why we need to increase our intake. Fiber is a plant-based, non-digestible carbohydrate. It’s present in foods like fruits, vegetables, whole unprocessed grains, legumes, and nuts. Non-digestible means exactly what it says- our bodies aren’t able to untangle their complex structure and absorb them for energy. Instead, it travels through the digestive tract. However, it’s this journey through the gut where all the magic happens.
There are two types of fiber. There is soluble, which dissolves in water, and insoluble, which does not. For all intents and purposes, know that both are important, but the following imagery may help. The soluble fiber mixes with water to form a gel-like substance. Insoluble fiber is a bulking agent, adding structure to the gelatinous mix formed by the soluble fiber. In my mind, I think of slime (the stuff all the kids are making these days) and a strainer. Picture pouring a mildly thickened liquid from a pitcher into a bowl- this is digestion of food devoid of fiber. Now picture that liquid thickened to the texture of slime (addition of soluble fiber). Now picture pouring the slime through a strainer (addition of insoluble fiber). You can see now how adding both types of fiber significantly slows down both how fast and how much food makes it through. It’s the same process in our gut. Consuming both types of fiber slows down how much and how fast foods, especially carbohydrates, are absorbed. You also feel more full and satisfied with less food, which helps prevent overeating.
When we eat foods devoid of fiber, they are rapidly absorbed to create energy. This sounds like a good thing, however, our bodies were designed to thrive on a slow, steady absorption of energy. Without fiber, you see a rapid increase in serum blood sugar, which subsequently triggers a rapid rise in insulin to help drive all of this sugar, or glucose, into the cells to be used for energy. Blood sugars then quickly plummet, leaving your body wondering when its next source of energy will arrive- hello energy crash. This is when hunger starts to kick in. Day to day, on a diet low in fiber you may experience ups and downs in energy. In the long term, frequent surges and high levels of insulin are what lead to insulin resistance, diabetes, inflammation, and heart disease, which is why we think high fiber diets protect against these things.
You now understand why eating fiber-rich foods help create sustained energy instead of highs and lows, help you feel fuller longer, prevent overeating, and lest we forget, help keep you “regular.” More importantly, it protects against rapid absorption of carbohydrates and high insulin levels. This is why diabetics are taught when calculating carbohydrates to subtract the grams of fiber from the total grams of carbohydrates because essentially fiber creates a net loss. All of these factors help keep our hunger and our waistlines under control.
Something to keep in mind, if you were thinking of picking up a fiber supplement and throwing it in your morning shake, is that all fiber is not created equal. Fiber you scoop from a jar has been extracted from natural sources and finely ground to a powder. Unfortunately, this has minimal if any of the positive effect we would receive from the natural fiber source. The manipulation breaks up the insoluble fiber, rendering it useless as a binding and bulking agent. Unfortunately, when we buy “high fiber” cereals and breads, we don’t have a great way of knowing how much the fiber has been processed because the “whole grain” classification has very loose criteria. Likewise, when you throw your fruit in a blender for a smoothie or protein shake, you’ve pulverized the insoluble fiber again rendering it unable to do its job. In order for you to get the most benefit from fiber, it should be eaten in its whole form and you need both soluble and insoluble fiber for maximal benefit.
I chose not to touch on the role of fiber as a prebiotic and its relationship to our gut health and microbiome, certainly a hot topic that deserves its own blog post. The basic role of fiber is so important I don’t think we necessarily need to dig into every nook and cranny to understand we should up our intake.
If you’ve followed me for long you know I don’t recommend micromanaging your diet. I believe in making general shifts towards better choices to optimize your health, which is more sustainable. So I challenge you this week not to analyze your food labels and attempt to get your 25-38 grams in daily, but rather pay attention to how many servings of fruits, vegetables, nuts, etc you’re consuming. If you’re on the low end, don’t panic, you’re right in line with everyone else. But it’s time to be intentional about increasing your fruits and vegetables. Try to come up with fiber-rich snacks to have around. Set a goal of including at least one fiber food source at each meal.
Also, be aware that if you’re going from minimal fiber consumption to all of a sudden a high fiber diet, your gut may take some time to adjust. Don’t be scared of the rumblings, feeling of bloating or fullness, or even more frequent runs to the bathroom. With time your digestive tract will adjust and start working more efficiently.