Fiber - Who Is She?

If you follow nutrition trends, you may have noticed that fiber is having its (long-deserved) time in the spotlight – kind of like in a classic coming of age rom-com movie, when the quiet nerdy kid takes off their glasses and suddenly becomes popular (fiber is so Mia Thermopolis-coded). People are starting to catch up to what dietitians and health professionals have been saying for decades: that dietary fiber is a crucial player in many aspects of health. It’s not a coincidence that diets high in plant-based foods like fruits, vegetables, and legumes (all of which naturally contain fiber!) are associated with so many health benefits (ref; ref; ref).

But seriously...what is Dietary Fiber? Dietary fiber is the carbohydrate portion of foods that cannot be completely broken down during human digestion. Because humans lack the enzymes needed to break it down, dietary fiber does not get absorbed into the body via the bloodstream and instead passes through the digestive tract, arriving in the colon intact. Now we know what you’re thinking: don’t we want our body to absorb nutrients? Well, yes, but also no! In the case of fiber, its health benefits are only realized because it’s not being absorbed directly into the bloodstream. As it passes through the gut and arrives at the colon, dietary fiber can help to trap and clear away fats and cholesterol, slow digestion, and promote the growth of “good” gut bacteria.

Most fibers are complex carbohydrates that are naturally occurring in the cell walls of plants. They can be categorized based on a few primary attributes: Solubility - whether they dissolve in water (soluble fiber) or not (insoluble fiber). Viscosity - whether they thicken in water and form gels that trap bile and slow down the absorption of nutrients (viscous) or not (non-viscous) Fermentability - whether they are metabolized by the microbiota in the colon (fermentable) or not (non-fermentable).

Dietary Fiber and Health Soluble, viscous, readily fermentable fibers are thought to decrease absorption of fatty acids, increase excretion of LDL cholesterol (ref, ref), and decrease absorption of glucose (ref, ref). In this way, soluble viscous fibers are thought to reduce risk for cardiovascular disease and type 2 diabetes (ref, ref). These fibers are found in high concentrations in foods like oats and barley.

Soluble, viscous, non-fermentable fibers like psyllium can also help with clearance of LDL cholesterol and glucose (ref). In addition, they retain their water-holding capacity in the large intestine, conferring a stool-normalizing effect (ref).

Soluble, non-viscous, fermentable fibers are thought to confer prebiotic effects – meaning, they stimulate the growth and/or activity of beneficial gut bacteria..(ref). By feeding the “good” bacteria, these fibers help stimulate the immune system, break down potentially toxic food compounds, and synthesize certain vitamins and amino acids (ref). Inulin (a type of fiber found in plants like onion, garlic, barley, Jerusalem artichoke, and chicory root) is an example of a soluble, non-viscous, fermentable fiber that has a prebiotic effect (ref).

Insoluble, non-viscous, poorly fermentable fibers include wheat bran, cellulose, and lignan. These fibers help to improve bowel regularity and can aid in weight management (ref) through their stool-normalizing effects and bulking of gastrointestinal contents.

Dietary Recommendations for Fiber/Sources Health authorities recommend that men consume 38 grams of fiber a day and that women consume 25 grams (ref). But it turns out that people in the US are falling quite short of this recommendation - in fact, the 2020-2025 Dietary Guidelines for Americans lists dietary fiber as a “nutrient of public health concern” due to insufficient intakes generally (ref). Good sources of dietary fiber include fruits, vegetables, whole grains, legumes, nuts, and seeds. All of these plant based foods contain a mix of soluble and insoluble fiber, and they are the main sources of fiber recommended by health professionals because they have the added benefit of contributing many other important nutrients to the diet.

Dietary Fiber in Impossible Foods Products Our plant-based meat has a clear benefit over the animal when it comes to dietary fiber. Impossible products contribute 1 - 7 grams fiber per serving while animal meat contains 0 grams. The main source of dietary fiber in Impossible Foods products is soy protein, which is largely insoluble fiber, and our other ingredients contribute smaller amounts of fiber as well.

A question we sometimes get is whether the fiber in our product can affect the digestive system, given the content of soluble and non-fermentable fiber. One important consideration is that how an individual reacts to the fiber content of a food can often be significantly impacted by how much fiber they are used to consuming. Thus, if someone is not accustomed to consuming a high amount of fiber in their diet, it is often advised that they increase their intake of fiber gradually, rather than suddenly (ref).

Our Ongoing Commitment to Health and Nutrition All Impossible products are formulated to meet health and nutrition targets set by our team of experts, and in alignment with various health authorities across the world. We’re committed to continuing to stay abreast of the current scientific literature on nutrition so that we can create meat alternatives (aka meat from plants) that are not only better for the planet, but also help consumers meet their nutrition needs.