Keto diet - low-carb diet for athletes and health enthusiasts

Translated by: Avramov Maxim - an enthusiast of a healthy lifestyle and author of the website ilovemysport.ru.
2020-03-12

The ketogenic diet generates a lot of conflicting opinions. Is it necessary for athletes and healthy lifestyle enthusiasts?

What is a Keto Diet?

The keto diet, or ketogenic diet, is essentially a low-carbohydrate diet. Initially, it was used to treat various diseases. Later, its application extended into dietetics.

Like all living beings, we need energy. We use glucose as fuel. During the keto diet, we limit carbohydrate intake to 20-30 grams per day. As a result, glucose levels drop to a critical minimum, causing insufficient energy for the body's normal functions. At this point, the body seeks an alternative energy source known as ketosis. Ketosis is a state in which the body derives energy from the breakdown of fats while the cells are in a state of carbohydrate deprivation. Consequently, ketone bodies are produced as a fuel source.

In an ordinary person, blood contains a small amount of ketone bodies. The body receives sufficient glucose, eliminating the need for additional energy sources. However, in ketosis, the concentration of ketone bodies sharply increases. A similar situation occurs for those who fast for several days, but this method is more harmful than beneficial. When following the keto diet, individuals do not experience hunger, continue to eat, and obtain essential nutrients while simultaneously reducing body weight and fat levels.

Popularization of the Keto Diet

If you had asked me five years ago whether the keto diet could become popular, I would have said never!

I have been on the keto diet for six years. It has helped me overcome ulcerative colitis. I have a lean body and have abandoned the bodybuilding paradigm of six meals a day.

I must admit that the “Cult of the Keto Diet” slightly irritates me. Many "gurus" without relevant qualifications generously share their “individual” worldviews on social media.

This leads to the emergence of identical advice. I have read numerous blogs stating that you shouldn't consume more than 30 grams of carbohydrates per day or 1.2 grams of protein per kilogram of body weight. Otherwise, you won't reach ketosis.

This may apply to a 50-year-old man with excess body weight. But what about athletes and healthy lifestyle enthusiasts?

The truth is that athletes engaged in strength sports and martial arts desperately need sufficient protein and carbohydrates. Otherwise, they won't have enough energy for performance. Achieving ketosis is not their primary goal. It’s about effectively adapting to fat for improving strength, endurance, and recovery. This is why many athletes fail when they blindly follow “guru” recommendations for maintaining low-carb diets.

So, we’ve established what the keto diet is and its necessity for an average person. But what about those who embrace a healthy lifestyle? How many grams of protein and carbohydrates do athletes require to continue benefiting from fat adaptation? To answer this, we’ll look at research on keto adaptation in athletes.

The Impact of the Keto Diet on Athletes' Bodies

In 2016, Dr. Jeff Volek and his team published a paper titled “Metabolic Characteristics of Keto-Adapted Ultra-Endurance Runners.” This study is important for several reasons.

First, it is one of the few random sampling studies involving living subjects, comparing athletes on high and low carbohydrate diets under competitive conditions.

Second, it is the only study comparing fat and carbohydrate oxidation among athletes on high and low carbohydrate diets. We also have insight into the athletes' diets during competitions.

Third, this study uniquely compares glycogen concentration before and after workouts.

The subjects were 20 high-level athletes actively participating in ultramarathons or triathlons.

Twenty months before the study began, half of these athletes followed a high-carbohydrate, low-fat diet (HCLF), consisting of approximately 60% carbohydrates, 25% fats, and 15% proteins. The remaining athletes adhered to a low-carbohydrate, high-fat diet (LCHF), essentially a keto diet, consuming 10% carbohydrates, 70% fats, and 20% proteins.

After following their respective diets, they underwent a series of tests in a lab, including a maximum oxygen consumption (VO2 max) test and a 3-hour run at 64% of VO2 max on a treadmill. The VO2 max reaches its peak when oxygen consumption remains stable despite increasing workload. In both studies, the rates of fat and carbohydrate oxidation were measured using indirect calorimetry.

Maximum oxygen consumption is the maximum amount of oxygen that a person can utilize in one minute, measured in milliliters. This data is used as a clinical indicator of vitality and a criterion for aerobic capacity. In cyclic sports, maximum oxygen consumption is a crucial indicator of an athlete's performance.

Before, during, and after the 3-hour marathon, physicians analyzed glycogen levels in the athletes’ muscle tissue, took blood samples, and performed biopsies on muscle fibers located on the outer surface of the thigh. Here’s what they discovered.

During the VO2 max testing, the first group of athletes oxidized fat twice as quickly as the others.

During the VO2 max test, it was found that LCHF athletes reached their peak fat oxidation at 70% of their VO2 max, while HCLF athletes reached it at 55%. It was previously believed that athletes on low-carb diets could not perform intense exercise without switching to glucose. However, this study demonstrated that fat-adapted athletes can burn fat even during intense exercise.

The most surprising finding was that the subjects had the same amount of glycogen in their muscle tissue before and after the 3-hour marathon. This is peculiar, considering that LCHF athletes had restricted carbohydrate intake for 20 months. Thus, a low-carb, high-fat diet is more effective at retaining glycogen in muscle tissue.

But why do athletes and health enthusiasts need research that analyzes endurance?

The ability to oxidize fat better and retain glycogen indicates that fat adaptation is a potential way to effectively burn fat, build muscle mass, enhance strength, and improve athletic performance.

How to Increase Muscle Mass on a Low-Carbohydrate Diet with Low Protein?

Well, now you might say that your brother or friend was on a keto diet. Now he’s weak, constantly tired, and looks unhealthy. There’s no talk of impressive muscle mass.

This usually happens when athletes adhere strictly to guidelines that are not meant for them.

If you are on a keto diet for medical reasons—such as cancer or epilepsy—you need to consume a lot of fats and little protein with carbohydrates.

If you lead a sedentary lifestyle, struggle with excess weight, and can't exercise, you will need to adhere strictly to the keto diet for weight loss. But for athletes and health enthusiasts, this is unnecessary.

For example, in Volek's study, the average weight of LCHF athletes was 69 kilograms. Their diet consisted of 226 grams of fats, 82 grams of carbohydrates, and 139 grams of protein. This is more than the 30-50 grams of carbohydrates recommended by some keto “gurus.”

Remember that it was Dr. Jeff Volek who conducted this research and analyzed it. Moreover, Volek, along with Stephen Phinney, literally authored a book for athletes on low-carbohydrate diets.

There’s a noteworthy phrase in the book: “...some people may need less than 30 grams of carbohydrates a day, while others may require up to 100 grams and still remain in a state of nutritional ketosis.” If you are a healthy person who trains with weights or engages in intense exercises, you will likely need those 100 grams.

Regarding protein, these athletes consumed 2.1 grams of protein per kilogram of body weight. Scientifically, this is more than enough for muscle mass gain.

In fact, a properly formulated low-carbohydrate diet for athletes cannot be low in protein by definition. Of course, if you consume an excess of protein—4-6 grams per kilogram of body weight—you won’t be able to adapt to a keto diet. This principle works the other way around: low protein intake leads to a decrease in performance and an inability to gain muscle mass.

Adapting to the Keto Diet

Athletes who want to be strong and wish to see an increase in muscle mass should not adhere to a strict keto diet. However, this doesn’t mean they can’t reap the benefits of fat adaptation.

You may still have to go through that two-week period where your body learns to use fat reserves as fuel. Although this will be challenging, any diet is a stress for the body. Remember to monitor your cortisol levels! Choose your adaptation period carefully. Take a break from training. A vacation might be the best time to start a keto diet. Aim for a macro ratio of 70% fats, 20% proteins, and 10% carbohydrates.

After this two-week phase, you can slightly adjust your eating pattern. On training days, you should consume 60% fats, 25% proteins, and 15% carbohydrates. Reserve a larger portion of carbohydrates for the end of training or the evening. On non-training days, you can reduce your carbohydrate intake to 10%.

Even if your body does not produce enough ketones to achieve a state of ketosis, you will still gain benefits from fat adaptation. Fat oxidation will increase, and glycogen concentration will rise. And yes, you will certainly lose weight.

Remember, don’t listen to every keto “guru.” You don’t necessarily have to achieve a state of ketosis. Your goal should be fat adaptation.

Translation of the article from the site Muscle&Strength.