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1. Cycling Ketogenic Diet


Nowadays, we can see two trends in which dieticians are looking for better and better methods and ways to feed athletes. The main goal of sports nutritionists is to take care of weight control, adequate energy supply, help in post-workout regeneration, selection of appropriate supplementation and planning nutrition during competitions and trainings.

The first trend is based on drawing energy from the high supply of carbohydrates during the day. You can see in it the constant care for equalization of glycogen reserves, which is the energy store for our body during exercise.

The second one is the nutrition model called ketogenic diet and this is the current we will discuss in this article.

2. Ketosis – What Is It?


In order to be able to write about a ketogenic diet, it is first necessary to explain the state in which the body needs to be introduced during this model. Ketosis is a metabolic state in which the main source of energy for the body becomes ketone bodies, and the level of insulin and glucose in the blood is stable and low.

When the glucose concentration in the blood drops, the body activates metabolic pathways, whose task is to obtain energy from sources other than glucose. While for several hours we do not provide carbohydrates, the body is forced to draw energy from fats. The liver uses the incoming fatty acids, which are intensively broken down from the fat tissue to produce ketone bodies (ketogenesis). Ketone bodies are acetoacetate, 3-hydroxybutyrate and acetone. Ketogenesis takes place only in the liver and then the ketone bodies are transported to the blood and tissues that use them – the brain and skeletal muscles.

The brain uses ketone bodies in proportion to their concentration in the blood. In the case of muscles – the higher the concentration of ketone bodies in blood, the lower their use by muscles.

The use of ketone bodies by the body is influenced by :

  • Physical activity
  • Construction and proportions of muscle fibres
  • The level of training
  • The concentration of ketone bodies in the blood.

3. Ketogenic Diet


The first records of the ketogenic diet dates back to the end of the 19th century, and the heyday of observation and its application in epilepsy dates back to the 1920s.

In a ketogenic diet, attention should be paid to the appropriate level of macroelements, so that the body can switch to the absorption of energy from fats:

*Carbohydrates should be reduced to 20g/day or not exceed 5% of the total energy supply during the day.

The sources of carbohydrates in the ketogenic diet should be only vegetables such as:

lettuce, rocket, lamb’s lettuce, lamb’s lettuce, spinach, cucumber, celery, cauliflower, broccoli, Brussels sprouts, onion, asparagus

*protein should be kept within 1.2-1.7g/kg bodyweight/day or should not exceed 15-20% of the total energy supply during the day

Too much protein supply during the day may inhibit the process of ketogenesis.

Sources of protein in the ketogenic diet:

beef, pork, poultry, game, fish, shrimps, mussels, lobsters, smoked meats, eggs, cream, cream cheese, yellow cheeses.

Attention should be paid not to consume manipulated meat products, processed cheese products, milk, yoghurts, soft cheeses.

*take care of a high supply of fats – up to 75% of the total energy supply during the day

Sources of fats in the ketogenic diet:

olive oil, vegetable oils, butter, nuts, almonds, avocado, fatty meat, fatty fish, eggs

Pay attention to the carbohydrate content of nuts, almonds and avocados and select the quantity of these products so as not to exceed 20g of carbohydrates per day.

It is also worth noting that the supplementation of sodium (3-5g/day) and potassium (2-3g/day) should be taken care of.

The ketogenic diet is a dietary model that requires a rigorous approach and meticulous observance of the recommendations. Failure to adjust to the restrictions of this diet results in a decrease in the concentration of ketone bodies in the blood, and consequently the loss of ketosis, deterioration of mood and physical fitness.

4. Keto Adaptation


It is the most difficult period of ketogenic diet. It occurs at the beginning of the diet and usually lasts 5-7 days. When the level of muscle and liver glycogen is exhausted and the level of ketone bodies in the body increases to about 4 mmol/l, we can see a deterioration of mood and dehydration. After the adaptation period, when determining the training, you should take into account the possibility of further deterioration of mood and exercise ability of the athlete, which may last about 7 days.

After this time, the quality of the use of ketone bodies by the muscles increases and the rate of fat oxidation during moderate intensity efforts increases.

Glucose is the best source of energy for the brain and skeletal muscles. The reason for adaptation to the ketogenic diet is adaptation to reduced blood glucose levels. The body maintains blood glucose levels at a physiological level in the case of a ketogenic diet, despite a limited supply of carbohydrates. This is done by activating the gluconeogenesis pathway, the product of which is glucose, and the substrates are glucogenic amino acids (protein breakdown products) or glycerol (fat breakdown products). If the ratio of carbohydrates, proteins and fats in the ketogenic diet is not observed, the body’s ability to produce glucose on the gluconeogenesis pathway decreases, and as a result, hypoglycemia and even coma may occur.

An important issue concerning the maintenance of a ketogenic diet is the regular measurement of ketone bodies in blood as an indicator of the effectiveness of the diet.

An absolute contraindication to the use of ketogenic diet is the impaired oxidation of fatty acids found by a physician. This is the case with deficiency of carnitine or enzymes involved in the processes of fatty tissue breakdown.

5. Ketogenic Diet in Sport – Pros and Cons



  • The ketogenic diet can be used with very good results in case of weight loss. A well-chosen diet will reduce body fat and at the same time maintain a lean body mass.
  • This is mainly due to a decrease in energy supply and an increased supply of protein and fats, which cause a greater feeling of satiety, regulate the levels of hormones responsible for hunger and satiety (ghrelin and leptin) and the effect on the reduction of appetite.
  • The ketogenic diet will have the greatest impact on endurance sports. The effect of better use of ketone bodies during exercise may improve the final result by reducing glycogen consumption. Endurance disciplines stimulate the body to the greatest extent to capture energy from oxygen sources, which are ketone bodies from the breakdown of fat tissue.

After the keto adaptation and application of the ketogenic diet 5-6 days before the competition, alternating with a high-carbohydrate diet (with different levels of effort) allows for an increased rate of fatty acid oxidation and a reduced rate of glucose oxidation during the start. This contributes to an increase in performance. During prolonged workout it is possible to apply special nutrients containing ketone esters, however, it should not be done for the first time at competitions, but tested in the preparatory period due to the risk of gastrointestinal problems.



  • Ketogenic diet is not a suitable nutrition model for athletes in sports with high intensity of effort (team sports, sprints). In such disciplines the main source of energy will be glucose and ATP resulting from the decomposition of phosphocreatine.
  • A big problem of using only a ketogenic diet is frequent feeling of fatigue during prolonged exercise. This is related to increased levels of ammonia and tryptophan in the body. The increased rate of oxidation of ketone bodies increases the uptake of tryptophan by the brain and affects the increase in the level of serotonin, which accelerates the feeling of fatigue.
  • The ketogenic diet is not suitable for muscle building. It reduces the release of insulin-like growth factor type 1 (IGF-1), which affects post-workout regeneration, muscle protein synthesis and muscle cell growth.
  • The model of nutrition based on high restrictions and requiring a dietary regime has a bad influence on the athlete’s relationship with nutrition. An athlete who has to follow absolute dietary recommendations for a long time feels the effect of being locked in a dietary cage and, as a consequence, may “throw himself on carbohydrates” unacceptable weight gain, inhibition of the ketosis process or obsessive thinking about food.

6. Example of a Day Cycling Ketogenic Diet Plan – 2500 kcal



Scrambled eggs with mushrooms and cucumbers

  • 5 eggs
  • 2 tablespoons of linseed
  • 1/2 cucumber
  • 2 tablespoons of olive oil
  • 5 mushrooms
  • 2 tablespoons of cream 18%
  • a pinch of salt and pepper

Second Breakfast:

Mackerel salad

  • 1/4 of each onion
  • 1 piece fresh mackerel
  • 2 pickled cucumbers
  • 2 tablespoons of linseed oil
  • 2 tablespoons of green olives
  • 2 tablespoons of chopped parsley


Beef tenderloin steak and vegetables

  • 1 piece of fatty tenderloin of beef
  • 2 tablespoons of olive oil
  • 1/4 cucumber
  • 1/2 of the handful of Brazil nuts
  • 5 handfuls of lamb’s lettuce
  • 5 asparagus pieces


Pancakes with pork neck and kale

  • 2 eggs
  • 2 handfuls of kale
  • 1 and 1/2 tablespoon of olive oil
  • 5 cherry tomatoes
  • 100g of pork neck
  • 5 tablespoons of water
Coach Damian

Damian is a head coach and founder of Cyklopedia, which was created with one goal to help everyone be faster cyclists by structured training plans, healthy recipes, and nutrition plans. Damian is racing and coaching for over 10 years, working with athletes all around the world.

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