Now that you know everything you need to know about protein, and how much of it to eat, it’s time to figure out how much carbohydrate you should eat per day for CrossFit, weightlifting, and triathalon training.

The topic of how many carbs to eat per day is polarized. One camp says, “Eat low carb or get fat and die from cancer, diabetes, and heart disease.” The other camp is yelling, “Carbs are king and we need them all if we want to perform and feel our best!”

are sugar and carbs bad for you? She thinks carbs are the devil

In today’s lesson, we will take an objective look at the role of carbohydrates in the body. We will also cover

  • Why carbohydrates are important if you do CrossFit or high- intensity training.
  • How much carbohydrate you should eat per day for CrossFit, weightlfting and high-intensity exercise.
  • When carbs will make you gain fat.

The Role of Carbs in the Body

Carbohydrates are a very “easy” energy source for the body. They are easy to digest and easy to use. We store carbohydrates in our muscles and liver in a form called “glycogen.”

The muscles use glycogen to generate energy, especially during high-intensity exercise and weightlifting. Estimates from research peg maximum muscle glycogen storage at about 15 grams per kg of body mass. This is 1050 grams, or 4200 calories of energy, for a 155lb human whose glycogen stores are maxed out.

A limited supply of glycogen is also stored in the liver. Glycogen in the liver can be broken down and released into the blood when you have immediate energy needs.

The brain is the neediest organ in the body when it comes to carbohydrate usage.

First, the brain cannot store any energy for itself.

Second, about 20% of your energy needs at rest come from the brain, and its primary source of energy is carbohydrates. The only exception is during times of starvation or prolonged low-carbohydrate intake.

The same 155lb person would need about 115g of carbs per day from diet for the brain alone!

how many carbs do you need to eat for your brain


Do Carbs Make you Fat?

Carbs don’t have an inherent fat-storing property. Although many fitness professionals with a very basic understanding of insulin and carbohydrates might lead you to believe that high-glycemic carbohydrates spike insulin and are automatically stored as fat, this isn’t what research has demonstrated!

Research actually shows that even large meals of carbohydrate are primarily stored as glycogen and don’t necessarily lead to fat being added to the body. What carb intake does do is slow the rate that your body burns stored fat for energy.

Although carbs won’t make you fat by themselves, here are some conditions where carb intake would cause fat storage:

  1. You’re already eating more calories than you’re burning.
  2. You have low energy expenditure– little to no exercise, sedentary job, etc.
  3. Your glycogen stores are already pretty full.
  4. And then you eat a big meal containing carbohydrates.

These are easy conditions to meet, but we should lay to rest the idea that carbs are inherently bad for you.

Let’s now examine some of the reasons why carbs are important if you do CrossFit, weight training, or other high-intensity training.

Why You Need Carbohydrates For Performance

During-high intensity exercise or weightlifting, the body relies heavily on an energy system that uses carbohydrates stored in the muscle to generate energy to move.

How many carbs should you eat per day for crossfit if you love carbs

Some studies on bodybuilders show that typical resistance (weightlifting) training exercise routines deplete the glycogen in your muscle by 24-38%.

After exercise, the muscle will want to restore the energy it lost. Studies show that athletes who perform exercise that depletes the muscle’s glycogen and consume post-workout carbohydrates perform far better than subjects who did not consume carbohydrates after exercise.

How Many Carbs Should You Eat Per Day?

Download your calorie and macros for crossfit guide

It’s difficult to generalize a rule for how much carbohydrate a person needs. For that reason, it is important to understand the factors that will affect how much carbohydrate you should consume are:

  1. Your goals: Fat loss? Muscle Gain? Increased Strength? Better Endurance?
  2. Your current body fat and lean mass.
  3. Your current training regimen.

With that in mind, here are some general recommendations:

  • If you need to lose fat and already carry around extra fat, drop carbohydrates to 25% of energy intake.
  • If you want to gain muscle, or you struggle to keep weight on, eat about 50% of energy from carbs.
  • If you just want to maintain your build, and have the energy to train, eat about 40% of energy from carbs.

At Beyond Macros, we take all of this and more into account when calculating our clients’ macronutrient needs.

Since it’s a rare case where we prescribe ketogenic diets for our CrossFit and strength training clients, the brain’s daily need for carbohydrate is the “floor” we set for client carbohydrate intake. This is usually between 100-150g depending on the client’s size.

For clients who already have low body fat and are looking to gain mass or compete in competitions from the CrossFit Games to local throw-downs, we generally recommend a higher carbohydrate intake of about 40-50%+ of total energy per day depending on factors including carbohydrate tolerance, body fat, and training volume.

As we observe a client’s carbohydrate tolerance, recovery from exercise, progress towards their goals, and when their training volumes change, we will make adjustments to their carbohydrate intake to find the optimal level to support their specific goal.


What About Carbohydrate Quality and Timing?

Carbohydrate quality and nutrient timing are more advanced nutritional considerations. We will publish some resources on these subjects later, but dialing in quantity is an important place to start!


Coming Up Next

We’re going to take a look at the critical role fat plays in the body, the different types of fats, how much of fat you should be eating, and sneaky food sources of fats.