Dietary Fiber: Build Muscle Better

Most (~93%) of Americans do not get enough fiber in their diet. A big reason is that few understand what fiber does for them. Fiber is indigestible; it offers no nutritional value, yet it is still extremely important for your health. Having adequate fiber has been associated with healthier cholesterol and blood sugar levels (for reasons discussed below) and lower risks of various diseases (by being super good for your microbiome). We will focus on the critical and unexpected role fiber has in building your muscles.

When you ingest any form of protein, it is broken down in the stomach by pepsin and in the small intestine by trypsin and chymotrypsin into individual amino acids and dipeptides. From there, the molecules filter through the intestinal walls and enter the bloodstream. There is, however, a limit to how many amino acids and dipeptides can be absorbed in a period of time. As a result, your body cannot absorb all the muscle-building molecules you ingest in a high-protein meal or protein shake. Since we want a high protein intake, the only way we can increase absorption is to increase the amount of time it takes.

There are several ways to accomplish this:

A high-fiber diet

Fiber, being indigestible, dilutes the chyme (food + stomach juice) entering your small intestine, thus giving your body more time to absorb the protein. In other words, if a lot of protein hits your intestines at once, there will be too much to absorb. However, if you mix in a bunch of fiber, then less protein hits your intestines at a time, which gives the intestines more opportunity to absorb the protein.

Drink a lot of water

This works the same way. Drinking extra water also dilutes down the protein entering your small intestine. This makes it take longer for your body to absorb all the nutrients therefore allowing more protein to be absorbed overall.

Eating more, smaller meals

It’s the same idea as above but instead of less food entering your small intestine at once from being diluted by fiber or water, less food enters your small intestine at once simply by having less food in your body at once.

To maximize the amount of protein your body absorbs, do all three. This is why, when you look at what professional body builders eat, you see that they eat a lot of high fiber foods like broccoli, drink tons of water, and eat nearly constantly throughout the day. It’s actually the biggest complaint of many body builders and movie stars, eating is a job.

Great fiber sources

My personal favorites. Oats, chia seeds, and broccoli. Fiber helps increase protein absorption so each of these should be paired with protein. I add 1 cup of oats to my morning shake and 2 tablespoons of chia to my post-workout shake. Broccoli and other leafy greens are part of many lunches and dinners.

Oats

Serving (0.5 c)

Calories 150

Total Fat 3 g 4%

Saturated fat 0.5 g 3%

Total Carbohydrate 27 g 10%

Dietary fiber 4.0 g 16%

Sugar 1 g

Protein 5 g

Chia

Serving (1 Tbsp)

Calories 60

Total Fat 4 g 6%

Saturated fat 0 g 0%

Total Carbohydrate 5 g 2%

Dietary fiber 4 g 16%

Sugar 0 g

Protein 2 g

Broccoli

Serving (148 g)

Calories 50

Total Fat 0.5 g 0%

Saturated fat 0.1 g 0%

Total Carbohydrate 10 g 3%

Dietary fiber 3.8 g 15%

Sugar 2.5 g

Protein 4.2 g