Keto And Running: A Good Mix?

The ketogenic diet is a popular, low-carb, high-fat diet that has been touted as a way to lose excess body fat, improve chronic health issues, and clear up skin conditions. But is it a good idea for runners? On the one hand, the keto diet may help runners improve their fat adaptation, sleep, and energy levels, as well as aid in weight loss. On the other hand, there is evidence that the keto diet may hinder athletic performance, especially in high-intensity workouts, as carbohydrates are still the best source of fuel for these types of exercises. Additionally, there are potential health risks associated with the keto diet, such as high cholesterol and kidney stones. So, while the keto diet may offer some benefits for runners, there are also drawbacks and potential risks to consider.

Ketogenic diets are based on legitimate science and are generally accepted as a lifestyle

The Ketogenic Diet, or Keto, is based on legitimate science and is generally accepted as a lifestyle. It is a high-fat, adequate protein, and extremely low-carbohydrate diet. The idea is to eat a lot of fats and very few carbs to force the body to burn fat instead of carbohydrates for fuel. Carbohydrates are broken down into glucose, which is the body's most accessible form of energy. However, fat molecules release 125% more energy than carbohydrate molecules when burned and are also much more plentiful in the body.

To burn fat for fuel, the body must be in ketosis, which is when the body is producing ketones to burn fat due to a lack of glycogen from carb sources. The ketogenic diet aims to keep the body continually in this state of ketosis, using ketones released by fat cells for fuel instead of glucose.

Keto is touted as an ideal way to lose excess body fat, improve chronic health issues, and clear up skin conditions. It has also been linked to improved sleep and energy levels, fat loss, and body recomposition. Additionally, there is a glut of studies that suggest much wider potential benefits, including anti-cancer effects and aiding in heart and brain health.

However, it is important to note that keto is a very restrictive diet, and there are several drawbacks and potential side effects, including constipation, high cholesterol, acidosis, and kidney stones. It can also be challenging to maintain, as it requires a complete overhaul of one's diet, and it may negatively impact athletic performance, especially for high-intensity runners.

While keto may not be the optimal diet for stereotypical carbohydrate-loving runners, it can be beneficial for ultra-runners who run great distances, as they are often entering into ketosis during their lower-intensity but longer runs. Leisure runners who are not concerned with racing or PRs can also benefit from a low-carb keto diet if they rarely participate in high-intensity workouts, as they may enjoy an enhanced body composition, increased satiety between meals, and reduced inflammation.

For high-intensity runners concerned with increasing speed or hitting a new PR, a full keto diet may not be ideal as it has been shown to decrease speed and power. However, some athletes can consume carbohydrates prior to a big race without removing themselves from ketosis, ensuring they have burned most of the carbohydrates consumed. Ultimately, only highly dedicated runners training for ultramarathons ought to consider the Keto Diet.

The keto diet forces the body to burn fat instead of carbohydrates for fuel

The keto diet is a high-fat, adequate protein, and extremely low-carbohydrate diet. It forces the body to burn fat instead of carbohydrates for fuel. Ordinarily, the body breaks down carbohydrates into glucose, which it uses for energy. However, when there is a lack of carbohydrates, the liver converts fat into fatty acids and ketone bodies. These ketone bodies pass into the brain and replace glucose as an energy source.

To remain in ketosis, the state where the body burns fat instead of carbohydrates, a person's carbohydrate intake needs to be less than 50 grams per day. This is a difficult threshold to meet, as it means most runners' favourite foods are off-limits, including legumes, lentils, beans, bread, starchy vegetables, and sauces.

The keto diet is popular for weight loss because it is very efficient at burning fat. However, it is not a sustainable diet for everyone. It can be challenging to adhere to such a restrictive diet, and there may be drawbacks such as constipation, high cholesterol, acidosis, or kidney stones.

While the keto diet may be beneficial for some endurance athletes, it is not ideal for all runners. Ultra-runners, who run great distances of 30 miles or more in single races, are most inclined to benefit from a keto diet as they often enter into ketosis during their lower-intensity but longer runs. Leisure runners who are not concerned with racing or PRs can also benefit from a low-carb keto diet if they rarely participate in high-intensity workouts.

On the other hand, high-intensity runners aiming to increase their speed or achieve a new PR may not want to try a full keto diet. Studies have shown that a keto diet can decrease speed and power, and may not supply enough energy for their intensity level. These runners may benefit from a variation of the keto diet, such as cycling between ketosis and simply low-carb, or consuming carbohydrates prior to a big race without removing them from their diet entirely.

The keto diet can cause side effects such as constipation, high cholesterol, acidosis, or kidney stones

The keto diet can cause a range of side effects, including constipation, high cholesterol, acidosis, and kidney stones.

Constipation is a common side effect of the keto diet due to the drastic reduction in carbohydrate intake. Carbohydrates like fruits and whole grains are some of the most common sources of fiber in the diet, and transitioning to a low-carb diet can lead to digestive issues. The keto diet can also be challenging to adjust to because of its very high fat content, which can also cause gastrointestinal upset.

High cholesterol is another potential side effect of the keto diet. The high saturated fatty acid content of this diet regimen may lead to increasing total cholesterol and low-density lipoprotein (LDL) cholesterol levels. Some individuals may experience a dramatic increase in LDL-cholesterol levels, particularly those with a genetic predisposition to cholesterol metabolism dysregulation.

Acidosis, or ketoacidosis, can occur when there are high levels of ketone bodies in the blood. Ketone bodies are acidic, and excessive excretion of these acids through the kidneys can cause a decrease in alkaline reserves or bicarbonate ions, leading to a reduction in blood pH. This can have negative effects on vital organs such as the kidneys and liver.

Kidney stones are a significant complication of the keto diet. The formation of uric acid and calcium oxalate stones may be due to chronic acidosis, dehydration, low urine pH, and fat malabsorption. The prevalence of renal calculi in people on the ketogenic diet is 3-10%, compared to 1 in several thousand in the general population.

The keto diet may hinder athletic performance, especially in high-intensity workouts

For runners, especially those who engage in high-intensity workouts, the body's quick conversion of carbohydrates to energy is essential. During high-intensity exercises, the body needs a quick and powerful source of fuel, which carbohydrates provide. On the other hand, fat molecules release more energy than carbohydrates when burned, but they burn slowly and steadily. While this may be beneficial for ultra-runners who are often entering into ketosis during their lower-intensity but longer runs, it may not be ideal for high-intensity runners.

Several studies have shown that the keto diet may hinder athletic performance, especially in high-intensity exercises. A study by researchers from Saint Louis University found that people on a ketogenic diet performed worse at anaerobic exercises than those eating more carbs. Another study on trained endurance athletes found that while there was no change in performance at lower speeds, the runners on the ketogenic diet became significantly less efficient at higher speeds, needing more oxygen and energy to sustain a given pace.

Additionally, a study on recreationally active endurance athletes found that while there was no change in performance at moderate intensity, there was a decrease in performance at vigorous intensity. Similarly, a study on short-duration exercises in athletes consuming a ketogenic diet found that while there was no change in performance at moderate intensity, there was a decrease in performance at vigorous intensity.

Overall, while the keto diet may have benefits for ultra-runners and those who engage in low-intensity exercises, it may hinder athletic performance, especially in high-intensity workouts.

The keto diet may not be sustainable in the long term due to its restrictive nature

The keto diet is restrictive in nature, and this may be a reason why it is not sustainable in the long term. The diet requires a complete overhaul of one's diet, as it involves consuming a high amount of fat, a moderate amount of protein, and a very low amount of carbohydrates. This means that most runners' favourite foods are off the table, including legumes, lentils, beans, bread, starchy vegetables, and sauces that are high in sugar.

The keto diet is also associated with several drawbacks and potential side effects, including constipation, high cholesterol, acidosis, and kidney stones. The transition period to ketosis can be particularly challenging, with people experiencing low energy, low mood, hunger, and poor sleep. Furthermore, the keto diet may not be sustainable for runners in the long term because it can lead to diminished athletic performance. Carbohydrates are still the best source of fuel for high-intensity cardiovascular running, and without them, runners may not be able to perform at their fastest.

While some ultra-runners may benefit from the keto diet as it can help them become fat-adapted, which is useful for longer races, most runners will struggle with the restrictions of the keto diet. It may be difficult to stick to the diet, especially with social commitments and family, and the intense adaptation period can hamper weeks of training. Ultimately, only highly dedicated runners training for ultramarathons should consider the keto diet.

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