This will be 1 of 2 blogs. One explaining the details of carbohydrates and how they work. The other will talk about tips on how you can enjoy more of them without storing fat.
Your Two Fuel Types
In essence, your body has two fuel sources... Carbohydrates and Fats.
Carbohydrates are the primary fuel source during weight training. Dietary fat and/or stored fat is what fuels everything else.
Think of carbohydrate as the rocket fuel for your workouts that allows you to train hard and with high intensity.
When you fail to get enough carbohydrates in your diet you’re lacking the class A fuel required to stimulate and grow as much muscle as possible.
Dietary Carbohydrates and proteins are similar in that the more muscle you carry, the more you require.
This is why people with more muscle can eat more junk carbs without getting fat. When consumed, carbohydrates are broken down into sugar (glucose) and release a hormone called insulin.
Insulin has two vital roles in building muscle...
Insulin drives excess carbohydrates into the muscles to be stored as muscle glycogen until your body needs to useit.
Insulin also drives amino acids into the muscle so more muscle can be made from weight training.
If you eat the right amount of protein but not enough carbohydrates, amino acids from protein are burned as fuel instead of being used to repair or build muscle tissue.
The right amount of carbohydrates does the following...
Produces enough insulin to promote muscle glycogen storage.
Produces ideal amino acid uptake in the muscles.
Inhibits fat storage (that's why low-carb works but not NO-carb).
Gives you powerful and intense workouts.
Maximum muscle growth.
Prevents muscle breakdown for fuel.
The Bad Side of Insulin
Now, let’s get into the unfortunate side of insulin...
As you may have guessed, the hormone insulin is a double-edged sword.
While it’s imperative that you consume enough carbohydrates, consuming excess amounts (including clean carbs) can accumulate fat storage or adipose tissue.
When you have consistently high insulin levels, the body increases the uptake of dietary fatty acids by fat cells which leads to an increase in body fat and can make your fat cells stubborn in “giving up“ fatty acids to be used as fuel.
You gotta find that healthy median between anabolic muscle building and fat accumulation.
The Liver, The Muscles and The Fat Cells
Let's say you have just done a 24-hour fast and your body is completely deprived of carbohydrates.
The next meal you eat that contains carbohydrates, those carbs are first going to go to the liver to be stored as liver glycogen (emergency sugar stores if you will). Depending on the person, the liver can hold anywhere from 30-60 grams of carbs.
Once the liver gets full of all the glycogen it can hold, whatever carbohydrate consumed after that will go to that persons muscles.
Here's why weight training is so important. The more muscle someone has or the more often they use thier muscles, the better. I'll explain why shortly.
And finally, when the muscles are fully taped the only place the body has to store carbohydrates is the person's fats cells. Resulting in whats called "fat spill-over".
Going back to what I said earlier...
You might not have any control over how many carbs your liver can hold. But you do have control over how much muscle mass you can have.
The more muscle you have, the more capacity your body has to store carbohydrates. And if you can store more, you can consume more without going into fat spillover.
When it comes to building muscle, all three macronutrients—carbohydrates, proteins, and fats—play a role. But protein is the most important.
Why?
Because it’s the only macronutrient that can create new muscle tissue—or any tissue in the body, for that matter.
When you eat protein-rich foods, your body breaks them down into amino acids, the building blocks of muscle. These amino acids are then used to repair and build new muscle tissue.
The best protein sources come from animal products that are raised on their natural diets, such as grass-fed beef, wild-caught fish, and free-range eggs and chicken. Animal proteins contain all eight essential amino acids, making them “complete proteins”—something our bodies can’t produce on their own.
If you follow a vegetarian or vegan diet, you can still get all essential amino acids by combining different plant-based protein sources.
HOW MUCH PROTEIN DO YOU NEED?
Your protein needs depend on three key factors:
1. Bodyweight – The more you weigh, the more protein you need.
2. Training Intensity – The harder you train, the more protein your body requires for muscle repair and growth.
3. Total Food Intake – Protein alone isn’t enough. Your body also needs the right balance of carbohydrates and fats. Without them, your body may convert protein into fuel instead of using it for muscle-building.
PROTEIN INTAKE GUIDELINES
The classic bodybuilding rule of thumb is 1–1.5g of protein per pound of lean body weight (not total weight).
Lean body mass is your body weight minus your body fat percentage. You can estimate this using calipers or a DXA scan, but if you’re not training for a competition, you can skip this step.
Instead, a simpler rule of thumb is to aim for 0.7–1g of quality, complete animal protein per pound of body weight (excluding plant-based protein sources).
To distribute this intake, divide your daily protein goal by the number of meals you eat (typically 3–6 meals per day).
Summary & Key Take Aways:
Only count complete protein sources. You don’t need to track the protein in foods like rice, pasta, potatoes, or oats.
If you train intensely but don’t get enough protein, you will lose muscle.
When your body lacks dietary protein, it breaks down muscle tissue to get the amino acids it needs. This process, known as catabolism, slows your metabolism and can lead to increased body fat.
During weight training, your body prioritizes fuel sources in this order: carbohydrates → fats → protein. If it runs out of readily available amino acids from dietary protein, it starts breaking down muscle instead.
To maintain and build muscle, you must eat enough protein to support your body’s needs. If you train hard but don’t consume enough protein, you’ll lose muscle and gain fat—simple as that.
No matter your goal, achieving a strong, lean physique comes down to maintaining a balance of low body fat and sufficient lean muscle mass.
If you want to dive deeper into the science of protein intake, I highly recommend this educational article by Precision Nutrition.
