The result of practicing very low-carb diets is that you have very little glycogen stored in your muscles and liver. Consequently, your body could be more dehydrated since water is a major component of glycogen.
Suppose you’re a physique competitor, an athlete, or a very active individual. In that case, your body primarily relies on fat as a fuel source via a biochemical process known as beta-oxidation. This can allow for thousands of fat calories to be metabolized as fuel.
A low-carb diet can be a significant disadvantage for athletes in high-intensity sports. The process of converting fatty acids into a usable fuel source, known as beta-oxidation, is much slower than the body’s process of converting carbohydrates into energy.
This means an athlete’s power will rapidly deplete during intense physical activity and won’t be replenished quickly enough to support continuous or repeated high-intensity activity demands. This underscores the urgent need to address the impact of low-carb diets on athletic performance.
This will apply to anyone who participates in high-intensity weight training, sprinting, power sports, or any other sport or activity involving recurrent, explosive bursts of energy. Unfortunately, your body cannot negotiate this. It is basic physiology.
Your body’s #1 preferred fuel source for high-intensity exercise is glycogen because it is the most readily available fuel for your muscles to utilize. During high-intensity exercise, the energy demands are so immediate that your body doesn’t have time to take in the required amount of oxygen that is necessary to process fat as a fuel source.
That’s why when you deplete muscle glycogen, there is a proportional increase in muscle fatigue. There is also an increase in muscle catabolism that occurs because your body metabolizes its muscle protein to convert it into the glucose that your body desperately needs.
Advanced athletes have recognized the importance of carbohydrates for quite some time. This isn’t all that surprising considering the amount of evidence that distinctly shows carbohydrates’ profound impact on the hormone ratio that is most significant to an athlete: the cortisol-to-free testosterone ratio.
The higher the cortisol levels and lower the testosterone levels, the less muscle mass an athlete can sustain. The greater the testosterone levels and lower the cortisol levels, the easier it will be for an athlete to maintain and increase the amount of muscle mass in their body.
Maintaining as much muscle mass as possible is paramount to any serious athlete.
There is something to be said about eating suitable carbs at reasonable times to maximize the advantages of carb consumption while preventing negative repercussions, like getting fat.
Here are a few guidelines you can follow:
One great example of a fast-digesting carbohydrate is Karbolyn®. Derived from potato, rice, and corn, this sugar-free powder is rapidly absorbed like glucose. Still, it provides long-lasting energy similar to the benefits of complex carbohydrates without waiting hours for the energy to kick in.
While low-carb diets may benefit weight loss or metabolic health, they are far from optimal for athletes and high-performance individuals. The reliance on fat oxidation simply cannot match the rapid energy demands of explosive, high-intensity training. Glycogen remains the primary fuel source for power, endurance, and muscle preservation.
By strategically timing carbohydrate intake—especially fast-digesting options like Karbolyn®—athletes can sustain energy, optimize performance, and protect hard-earned muscle mass. The key is not to fear carbs but to use them intelligently, aligning intake with activity levels to fuel success in training and competition.
The science is clear for those serious about performance: Carbohydrates are not the enemy—they’re an essential tool for peak athletic achievement.
