We are all trying to find an edge, something that will take us and our performance to the next level.
That edge takes the form of supplements. It takes the form of new training regimes. It takes the form of sport psychology.
It also takes the form of diet.
We have become increasingly aware of the intimate link between the types of food ingested and its impact on performance.
Scientific studies on the ketogenic diet and low carb diets have exponentially increased in the past 10 years. While research has undoubtedly added to the growing body of knowledge regarding how the body metabolizes different sources of fuel and what the human body needs to function optimally, it has also muddied the waters.
Some scientists believe we’ve become so enamored with the next big thing in the diet world, that we’ve forgotten what we’ve already known for centuries: carbohydrates are essential for optimal physical performance.
Carbs are essential is a conclusion drawn by an expert panel who convened in 2018 to discuss the latest science on macronutrient (protein, carbohydrates, and fat) needs for physical activity.
The panel consisted of Dr. Lawrence Spriet from the University of Guelph – a prolific researcher who studies the role of diet on exercise performance; Dr. Janet Rankin from Virginia Tech – a leader in the application of sports nutrition research and principles; Dr. Katherine Beals from the University of Utah – a certified specialist in sports dietetics; and Dr. Bob Murray – a former Gatorade Sports Science Institute director and researcher and lecturer in the area sports nutrition.
The panel agreed on the necessity of carbohydrates for physical performance, especially for high intensity exercise.
Do you do high intensity exercise? Then you need carbohydrates in your diet
More people than ever are doing High Intensity Interval Training (HIIT) and other forms of high intensity exercise. It cracked many published lists as one of the top fitness trends for 2019.
High intensity training allows you to burn more calories in a shorter amount of time, it increases your metabolic rate for hours after you’ve finished working out, it is associated with increased fat loss, and it can reduce heart rate and blood pressure. These are just a few of the known benefits.
High intensity exercise requires lots of energy.
Energy in the body is supplied in the form of adenosine triphosphate (ATP).
ATP is the biological molecule used by cells of your body as energy to do work. That work may be building new structures, breaking down old structures, and making your muscles move.
Proteins, fats, and carbohydrates can all be used to generate ATP to do work. How they get there is different for each macronutrient.
Proteins are used to generate ATP as a last resort.
The path to ATP from protein looks like this:
Protein –> Amino acids –> Keto acid –> Acetyl-CoA
Acetyl-CoA sugar is then used to generate ATP.
The path from fat to ATP looks something like this:
Fat –> Free fatty acid –> Acetyl-CoA
Finally, the path from carbohydrates to ATP:
Sugar –> Pyruvate –> Acetyl-CoA
High intensity exercise requires the use of fast-twitch muscle fibers. These muscle fibers are capable of breaking down proteins and fats to generate ATP, but they prefer carbohydrates because it is the only macronutrient broken down fast enough to support high-intensity exercise.
If you work out at a high intensity regularly, you definitely need carbohydrates.
Glycogen is the storage form of carbohydrates in the body. You can find it in the liver and in muscle.
Glycogen stores in fast-twitch muscles are the primary source of fuel during high-intensity exercise.
Data suggest that most athletes do not eat enough carbohydrates after they exercise to fully replenish glycogen stores.
If you don’t replenish glycogen stores, you end up with low glycogen in your muscle, your muscle has less fuel to generate ATP, and you cannot perform at your best.
The panel referred to a serious competitor who trained for four hours a day or more. They cited this competitor’s carbohydrate needs at a whopping 3,800 carbohydrate calories per day as required to maintain a high level of performance for an extended period of time.
Most of us don’t fall into this category of strenuous competition, but if you’re are an avid exerciser and doing high-intensity workouts on a regular basis, you are probably not fully replenishing your glycogen stores between workouts and your performance could be suffering as a result.
If you’re an avid exerciser doing high-intensity workouts on a regular basis and you’re on a low carb diet, your performance is definitely suffering during your workouts. You need carbohydrates to perform at your best.
How much carbohydrates do you need in your diet?
The panel of experts suggested 5-7 g/kg bodyweight for moderate exercisers and up to 8-12 g/kg bodyweight for very heavy exercisers.
Immediately before exercise and during exercise, high-carbohydrate foods and beverages are best. These are rapidly absorbed and provide muscles with the energy they need to maintain high-intensity performance.
Immediately after exercise, carbohydrate rich foods that can be quickly digested and absorbed can alter the hormonal environment in the body to support glycogen resynthesis.
The recent popularity of the ketogenic diet has led to many people avoiding carbohydrates in their diet. As more studies are conducted, research is synthesized, and critically evaluated the expert panel who convened in 2018 think we are going to relearn something about carbohydrates that we’ve known for decades: that they are essential for supporting high-intensity performance.
References and further reading