Dover’s Personal Trainer Explains Why Fiber Matters

Why Fiber Matters


Hitting your target protein, fat, and carbs is by far the most important factor in helping you achieve your ideal body. So does this mean that food sources don’t matter at all? No!

While food sources might be of less concern than meeting your macros, they still matter. This is because it’s important to get a minimum amount of fiber every day, and fiber is only found in certain types of food! So, what is fiber, where is it found, and what does it do?

Fiber is a type of carbohydrate found in fruits, vegetables, whole grains, and legumes that is resistant to digestion.


Fiber is famous for doing a few key things:
• Fiber “promotes regularity”
• Fiber slows the absorption of food leading to improved blood sugar control and satiety (fullness)
• Fiber can bind to and lower cholesterol


Many research studies have also found an association between a higher fiber diet and lower risk of cardiovascular disease, type II diabetes, and some types of cancer.

While many of us are familiar with these benefits, a new exciting benefit of fiber is starting to attract a lot more attention these days—the effect of fiber on bacteria in the intestinal tract!

Over 100 trillion microorganisms consisting of up to 1000 different species inhabit the gut. This is equivalent to about ten times the number of cells in the human body! These gut bacteria play an important role in immune health, gut health, and even metabolism and energy balance!

Eating a diet high in fiber has been shown to alter composition of the gut microflora to one more favorable to health. This is because fermentable fibers act as a food source to microbes living in the colon. When bacteria feast on fiber, they break the fiber down to produce short chain fatty acids (SCFAs).


These short chain fatty acids (SCFA) are used as energy by your body, and can supply up to 10% of your calorie needs! Because humans themselves can’t digest fiber, it’s widely believed that fiber doesn’t contribute calories and shouldn’t count toward carb or energy intake. But this is wrong. In reality, through bacterial fermentation, more than half of the fiber you eat can contribute to your daily energy intake (this is why Avatar Nutrition advocates tracking total carbs instead of “net carbs.”)

Not only do short chain fatty acids (SCFA) made by bacteria serve as a nutrient source, but they can also enter the bloodstream and act as messengers in the body to bring about even more benefits. Studies suggest that such benefits may include:

1. Improved glucose metabolism
2. Increased fat breakdown and reduced fat storage
3. Higher energy expenditure
4. Lower inflammation
5. Better immune health
6. Reduced appetite

By feeding gut bacteria and altering microflora to a more diverse and favorable profile, fiber may have an impact on overall health and even your metabolism! While the potential effect of fiber on the microbiome and all of these health parameters is certainly exciting, it’s important to remember that this complex field of study is in its infancy. To draw real conclusions, much more research is required.

It’s also critical to keep things in perspective. Many factors can influence the microbiome besides fiber including genetics, gender, environment, antibiotic use, stress, hormones, and overall health. Lifestyle factors like smoking, exercise, and total calories also have an impact. In fact, excess calorie intake and sedentary lifestyle are known to have a major adverse effect on gut bacteria.

So, with flexible dieting, keep your eye on the prize! Make sure to hit your macros to control your energy intake first and foremost, and make sure to include enough fruits, vegetables, whole grains, and legumes to meet your minimum fiber requirements to stay full, regular, and give you a healthy boost!


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