Bodybuilding & Fiber: How Much, Pros, Cons, & Best Sources

In addition to carbohydrates, fats, and protein, fiber is an important component that needs to be addressed in bodybuilding.

Even though fiber does not directly affect muscle growth, it helps to maintain digestion, and provides more bulk to meals, which gives a feeling of being full and satiated in a cutting phase. On average, bodybuilders should consume 25-28 grams of fiber daily for women and 31-34 grams per day for men.

There are some individual factors to consider when it comes to eating more or less fiber depending on the phase of training you’re in, which I’ll discuss below.  I’ll also explain certain circumstances where you want to avoid fiber if you’re a bodybuilder.

What Is Fiber?

Fiber is a type of carbohydrate.  However, our bodies are unable to digest it the same as other carbohydrates so it passes through our bodies undigested.  There are two types of fiber – soluble and insoluble.

• Soluble fiber can be dissolved in water and tends to help lower our blood cholesterol as well as our glucose levels. This helps to improve digestion to more easily break down your food for the energy you need. Foods containing soluble fiber include almonds, walnuts, raspberries, strawberries, lentils, oats, broccoli, and black beans.

• Insoluble fiber cannot be dissolved in water and therefore creates more bulk in your stool.  This is what helps to keep you regular and prevent constipation from occurring.  Foods containing insoluble fiber include fruits with skin, green beans, corn, whole grains and bran cereals.

It is important to note that you don’t have to be picky with the type of fiber that you are eating so long as you are choosing a variety of foods to eat.  This will help to ensure that you are getting a mix of both types of fiber in your diet.  

Should Bodybuilders Take Fiber?

Yes, bodybuilders should take fiber for the following reason:

• It keeps you full longer
• It keeps you regular
• It maintains blood sugar levels
• It adds bulk to your diet
• It reduces inflammation

It Keeps You Full Longer

Fiber can suppress appetite to help keep you feeling fuller, longer.  

Not only is this beneficial when you are in a cutting phase trying to lose body fat, but it is also helpful when you are trying to avoid grabbing for sweets and treats due to feeling unsatisfied or a potentially more restricted diet when bodybuilding.  

The reason for this is that fiber slows digestion and therefore keeps your body working to digest your food while keeping you feeling full and satiated.  In effect, you will be able to adhere to your diet more easily because you’re not feeling as hungry.

It Keeps You Regular

A high-fiber diet is beneficial if you struggle with irregular stools or constipation as it will help to increase the bulk of your stool as it passes through your digestive system, making it easier to pass.  As well, some soluble fiber creates a gel-like substance that helps to soften the stool.  

Meanwhile, some insoluble fibers irritate the intestinal wall and will send a signal to produce more water and mucus, which also help to pass stool through the digestive system with ease.  

It Maintains Blood Sugar Levels

Research shows that we are less likely to have a blood sugar spike when eating high fiber foods like fruits, legumes, and nuts than if we were to consume dietary glucose foods such as a chocolate bar or a sugary drink.

This is important because if we have an excess of glucose in our bloodstream, it signals to our bodies that we need to store that for later and will therefore store it as fat.  This is not helpful if you are trying to build muscle and lose body fat as many bodybuilders are.

It Adds Bulk to Your Diet

Not only does fiber add bulk to your stool but it will also add bulk to your diet.  

Many high-fiber foods come from green, leafy vegetables that are low in calories.  

When you are in a cutting phase of your bodybuilding journey, consuming more volume of food in a caloric deficit will help to ensure that you are remaining full and satisfied throughout the day.  

It Reduces Inflammation

With a high-fiber diet comes the benefit of reducing inflammation in the body.  

This is helpful while training because it will help to promote repair and restoration after a workout session.  

In addition, it can help to keep your body feeling strong and healthy to reduce the risk of getting sick and missing out on your workouts.

Drawbacks Of Taking Fiber When Bodybuilding

Although fiber has many benefits for you as a bodybuilder, there are also a few drawbacks worth recognizing:

Slower Release of Glucose Into the Blood

Consuming a high-fiber meal pre-workout may not be in your best interest. 

This is because fiber will slow down digestion and make it harder for your body to use glucose, which is generally consumed pre-workout for fast-acting energy.  

The key takeaway here is that you want to consume fiber outside the workout window, but avoid it 60-90 minutes before you plan to exercise.   

Fullness

Adding bulk to the diet is helpful while bodybuilding if you are in a cutting phase.  

However, if you are in a bulking phase, this can make getting enough calories challenging if you are not feeling hungry due to eating high-fiber meals.   

I generally recommend keeping fiber lower for those who struggle to eat enough calories. 

Digestive Discomfort

High-fiber diets (outside the daily recommended range) can cause digestive discomfort and produce gas, bloating, and abdominal pain.  

As such, you’ll want to stay within certain limits, which for bodybuilders depend on how many calories you eat per day.  Let’s address that now.

How Much Fiber Should Bodybuilders Have?

According to FeastGood’s Registered Dietitian, Brenda Peralta, the daily recommended intake for fiber is 25-28 grams of fiber daily for women and 31-34 grams per day for men. Interestingly, research shows that most Americans are only getting about 15 grams of fiber per day.  

Bodybuilders are slightly different though in terms of the recommended intake of fiber because they typically have a higher caloric intake compared with the average person.  

So, if you are looking to figure out exactly how much fiber to consume daily, use this simple calculation:

• Aim to get 14g of fiber for every 1000 calories consumed up to 3000 calories consumed. Therefore, if you eat 3000 calories per day, you should aim to get 42g of fiber per day.  

• However, if you consume more than 3000 calories, then ingesting more than 42g of fiber may lead to some of the negative consequences discussed above.  So to be safe, don’t consume more than 42g of fiber, and when you’re in doubt, it’s best to stick to daily recommendations of 25-35g of fiber.

These recommendations will be helpful when your diet changes depending on if you are in a caloric deficit for your cut, where you may be consuming fewer calories than normal, or in a bulking phase where you are consuming calories than usual in order to build muscle.  

• Related Article: 10 Ways To Add Fiber In Protein Shakes (With Recipes)

When To Have Fiber For Bodybuilding

Spread It Out Throughout The Day

Not only will this help to keep you feeling full but you will also be able to better regulate your blood sugar levels to get the most energy out of the foods that you are consuming.  

Optimally, you can spread out your fiber by consuming approximately 5-10g of fiber at each meal and 2-5g of fiber with snacks.  

If you are currently consuming a low-fiber diet and looking to increase this, gradually increasing your intake of fiber to avoid digestive discomfort is recommended.  Slowly adding in 2-3g of fiber daily at each meal is a great place to start until hitting the daily recommended values.

Post Workout Is Better Than Pre Workout

Keep in mind that consuming fiber slows down digestion if you are looking to utilize energy from carbohydrates more readily for your training sessions, so be sure to consume high-fiber snacks after your workout instead of before.  

Pair With Water

Be sure to drink enough fluids throughout the day to help your body use the soluble fiber that you are consuming since it is water-soluble.  These types of foods include oats, peas, beans, apples, carrots, and barley.

Best Sources of Fiber For Bodybuilders

No matter your food preferences, there are plenty of fiber-rich foods to choose from.  This is extremely helpful so that you can still get enough fiber intake no matter if you are in a bulking, maintenance, or cutting phase.

Here are some great high fiber food suggestions:

Grains

Legumes

Vegetables

• Check out my complete guide on best vegetables for muscle growth.

Fruit

Frequently Asked Questions

Here are some frequently asked questions for bodybuilding and fiber intake.

Is Fiber Good For Building Muscle?

Fiber doesn’t directly affect building muscle, but it helps excrete waste product from the body (from muscle building processes). This allows your body to clean any unwanted material, which helps reduce inflammation. A decrease in inflammation lades to better muscle recovery, which ultimately means more muscle growth. 

Does Fiber Increase Testosterone?

Research studies are inconclusive on whether fiber increases testosterone levels.  

What Do Bodybuilders Eat for Fiber?

Bodybuilders should choose a variety of foods including grains, legumes, vegetables, and fruit to get their daily recommended values for the day.

Do Bodybuilders Eat a Lot of Fiber Compared to Normal?

Depending on the number of daily calories consumed, it is recommended to consume 14g of fiber per 1000 calories consumed, without exceeding 42g daily.  Therefore, the daily fiber intake may be more for a bodybuilder because, on average, they consume more calories than a non-bodybuilder.  

References

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Ullrich IH, Albrink MJ. The effect of dietary fiber and other factors on insulin response: role in obesity. J Environ Pathol Toxicol Oncol. 1985 Jul;5(6):137-55. PMID: 2995635.

Swann OG, Kilpatrick M, Breslin M, Oddy WH. Dietary fiber and its associations with depression and inflammation. Nutr Rev. 2020 May 1;78(5):394-411. doi: 10.1093/nutrit/nuz072. PMID: 31750916.

Turner, N. D., & Lupton, J. R. (2011). Dietary fiber. Advances in nutrition (Bethesda, Md.), 2(2), 151–152. https://doi.org/10.3945/an.110.000281