Carbohydrates: The Most Important Macronutrient

In my opinion, the MOST important macronutrient for changing body composition is carbohydrates, and in the following section I will explain why. My entire diet is based around controlling insulin, which in turn involves paying attention to not only the amount, but the types of carbohydrates I am putting into my body. After the total calories that you consume are factored in, this is the most influential factor in gaining or losing body fat.

When it comes to most people’s weakness in eating a healthy diet, carbohydrates are usually the hardest to cut back on or change. Why is that? Why do we crave carbohydrates so much? It’s because carbohydrates cause the release of serotonin, or the “feel good” chemical in our brains. So, when people are stressed, depressed, lonely, anxious or have any other negative emotion, they have the urge to reach for carbohydrates, and usually it is the ones that are quickly broken down in the body. These include refined sugars, bread, ice cream, etc. “Comfort eating” is a real phenomenon and an extremely hard habit to break.

What Are Carbohydrates?

When you examine a carbohydrate, it is simply a sugar molecule. These molecules are processed by the body down into glucose, which is blood sugar. Glucose is used primarily by the brain, but also by all cells throughout the body for energy.

We usually only have about 4 grams of glucose circulating in our blood at one time. Since we can’t eat all the time, the body stores glucose in the liver and muscle tissue as something called glycogen. The liver and muscles can only hold a certain amount of glycogen, usually around 100 grams in the liver and 500 grams in muscle tissue. The amount of glycogen your muscles can hold varies from person to person, based on athletic ability and the amount of muscle mass. The body will also store 3 grams of water per 1 gram of glycogen.

This is the reason that so many people who try low or no carb diets lose weight quickly in the beginning. They are depleting their glycogen stores and not replenishing them, thus losing water weight.

Glycogen as Your Fuel Tank

I am going to try to keep this in simple terms and not get too scientific, so it is easy to understand. Think of your glycogen stores as your gas tank. Your body tries to keep your blood sugar or “fuel” at a stable level throughout the day. This allows all the metabolic functions in your body to carry on with a reliable source of energy.

When your blood sugar gets low, hormones in your body are secreted that signal glycogen to be converted back into glucose and released into the bloodstream. This is primarily done from the liver for normal day to day functions.

When you resistance train in the gym, the body signals the muscles that you are working to convert glycogen back into glucose to fuel the contraction process and keep your energy levels stable. The amount of glycogen you use up during a workout depends on the number of sets, intensity, length of training and other factors. A safe estimate would be 25-30% of your glycogen stores are used up in a normal hour-long workout.

So why is this important? This is important because we want to try and replenish those stores after our workout, but not exceed that amount plus what we burn up through metabolism before the next workout.

When Glycogen Stores Are Full

What happens when our glycogen stores are full, and we ingest more carbohydrates than we burn? The body still needs to take all that excess glucose out of our blood and store it, so if you guessed that it stores it in fat, you are right.

Blood sugar that is too high for an extended period of time can cause organ damage, vision loss and many other health issues, so it’s important that those levels are stabilized quickly after we eat. Individuals that live a sedentary lifestyle but still eat a large amount of carbohydrates gain body fat because the body does not need to replenish any stored glycogen in the muscles.

Fat cells are the reserve gas tank that our body puts all this excess glycogen into. When blood sugar gets high, the pancreas is signaled to release insulin. Insulin is a messenger that tells cells to open up and take the glucose out of our blood to store it. They are stored as fatty acids once our glycogen stores in the liver and muscle tissue are full. This is obviously not the goal if you are looking to lose body fat and have a lean muscular physique.

Using Insulin to Your Advantage

Insulin is not always a bad thing, and it is a very anabolic hormone that we can use to our advantage when it comes to changing body composition and building muscle. After our workout, when muscle glycogen has been somewhat depleted, we can use the opportunity to have insulin work to our advantage.

When we trigger the release of insulin at this time by ingesting carbohydrates, it tells our muscle cells to open up and store all that glucose as glycogen. This causes the muscle tissue to act like a sponge, soaking up glucose as well as amino acids and nutrients from any added protein, which helps them recover and grow!

Another benefit of spiking insulin post-workout is that it suppresses the hormone cortisol. Cortisol is a hormone that is released during any period of high stress on the body, including during a workout. Cortisol is a catabolic hormone that can actually make you retain body fat and burn muscle. I will cover insulin more in depth and optimal times for carbohydrate consumption in the nutrient timing section.

Carbohydrates: A Double-Edged Sword

So, as you can see, carbohydrates are an immensely powerful macronutrient that can stimulate muscle growth or the accumulation of bodyfat due to hormonal responses in the body. Many people in this day and age consume way too many carbohydrates for the amount of activity they have in their day to day lives.

This causes chronically elevated blood sugar levels which often leads to Type-II diabetes in adults. This is where the pancreas cannot produce enough insulin because the body has become insulin resistant. However, this condition can often be reversed by changing dietary habits.

Looking Ahead

We can learn a lot about what kind of carbs to eat, and when, by using the same tools that diabetics must use. I will talk about this especially valuable resource in the glycemic index section.