Low carb diets and endurance performance
When it comes to energy consumption, carbohydrates and fats are utilized while protein plays a crucial role in recovery. However, additional elements should be taken into account, including gender, dietary choices (such as veganism, religious beliefs, food intolerances, and allergies), culinary abilities, meal timing, and procuring meals while competing away from home.
In addition to this, ensuring proper nutrient intake through an athlete’s diet is crucial for maintaining good overall health, including immunity.
The nutrition of an athlete can be adjusted to enhance performance, involving both food choices and supplements. Among endurance athletes, a common approach that has shown effectiveness is adopting the high fat, low carbohydrate diet (LFHC), also referred to as the ketogenic diet.
Ketogenic diet
Carbohydrates are the body’s main source of energy, provided in the form of glucose. In the absence of carbohydrates, the body adapts by transforming fat into ketones in the liver for use as an alternate energy source.
The name given to this process is ketosis, and in order for the body to adjust, fat consumption should constitute approximately 80% of the diet, while keeping carbohydrates limited to under 50g per day (which is equal to a few slices of bread).
During long periods of sustained activity in endurance sports, the body depends mainly on carbohydrates as its primary source of fuel for training and competing.
At any given moment, around 1,600 calories of available energy is stored in muscle tissue (300g) and the liver (90g) in the form of glycogen, which is the storage form of carbohydrates.
Athletes need to consume carbohydrates regularly during an endurance event to replenish their depleted energy stores. The ketogenic diet appeals to endurance athletes due to the massive amount of energy stored in one kilogram of fat, which is approximately 7,700 calories.
By accessing this energy source, it is possible to decrease the necessity of refueling during physical activity. Depending on fat as an energy source may additionally lower the chances of digestive issues that certain athletes encounter when they consume excessive carbohydrates. It has also been proposed that following a ketogenic diet can decrease the buildup of lactate post-exercise, thus potentially improving recovery.
Does the ketogenic diet help endurance athletes
Now let’s tackle the million-dollar question you’re likely thinking: “Will the keto diet have a beneficial or detrimental effect on my athletes?” This is where the situation becomes complicated, as researchers looking to address this question have yielded contradictory findings in recent years. First, let’s explore some studies that support the keto diet.
At Waterford Institute of Technology in Ireland, a group of exercise scientists divided a total of 20 male endurance athletes into two groups. One group adhered to a diet that was high in fat but low in carbs, while the other group followed the opposite approach.
After a period of 12 weeks, both groups underwent a 100-kilometer time trial, a six-second sprint, and a critical power test. It was observed that both groups had similar performance in the long time trial, however, individuals in the keto-mimicking group exhibited better utilization of fat as a source of energy, showed improvements in their body composition, and experienced an increase in peak sprinting power per kilogram of body weight, possibly due to their reduced body fat percentage.
In the European Journal of Sport Science, a review was conducted to reconsider the common argument against the keto diet raised by its critics. It contends that athletes may struggle to sustain their performance and may reach a point of glycogen depletion where they cannot progress further, unless they consume carbohydrates before and during their workouts.
The authors proposed that the occurrence of ‘bonking’ may be attributed to the athlete’s inability to properly utilize their body fat. They suggested that the most effective way to enhance the body’s fat oxidation process is to reduce carbohydrate consumption to a level that induces nutritional ketosis (i.e., circulating ketone levels >0.5 mmol/L) and simultaneously increase fat intake for a few weeks.
Nonetheless, findings from alternative studies indicate that although the ketogenic diet brings about certain advantages for health, it does not enhance performance.
A recent review published in The Journal of Physiology argued that the evidence linking increased fat utilization to improved endurance performance in elite athletes is purely anecdotal. The review further concluded that a higher-carb diet had a greater body of evidence supporting its effectiveness in this aspect.
In a small-scale research conducted on endurance athletes in New Zealand, it was discovered that adopting a high-fat, low-carb diet had positive effects on specific skin conditions, inflammation reduction, and recovery improvement, as reported by the participants themselves. Nonetheless, the transition made it more challenging for them to undertake high-intensity training sessions and resulted in decreased energy levels during training.
How should we implement the ketogenic diet with the athletes
Dr. Frank Merritt, in his book “The 17 Hour Fast,” suggests that the human body struggles to handle a delta effectively.
In relation to this article, this implies that if one of your athletes is presently following a high carbohydrate and/or high protein, low-fat diet – which is the complete opposite of keto – they are likely to face negative consequences if you abruptly transition them to a ketogenic approach, similar to what was observed in the study conducted on New Zealand’s endurance athletes.
If you want an athlete to make a change, approach it in the same way you would in programming – gradually and consistently. Begin by assessing their current dietary habits and then establish a basic breakdown of macronutrient percentages.
Following that, you may commence with a gradual reduction of their carbohydrate consumption alongside an augmentation in the quantity of fat derived from food sources such as meat, eggs, fish, nuts, and seeds. Additionally, if there are no allergies or sensitivities present, full-fat dairy can be included in their diet.
Due to the lack of conclusive evidence and occasional contradictions in the research, it would be irresponsible to fully support or caution against the adoption of the keto diet.
Despite their physiological similarities, athletes will have unique responses to the same stimulus, be it a training method, recovery technique, or dietary plan. Hence, rather than enforcing a standardized program, it is essential to address the specific nutritional requirements of each individual client.
It may be more beneficial to avoid recommending specific eating approaches to your clients, and instead, impart the nutritional wisdom highlighted by Robb Wolf. He emphasized that regardless of following paleo, keto, vegan, or other diets, the primary goal should always be consuming whole and unprocessed foods that are rich in nutrients.
By doing so, they can ensure meeting their necessary macro and micronutrient requirements, steer clear of artificial components’ drawbacks, and effectively fuel and replenish their bodies without resorting to excessive measures.
Can the ketogenic diet help improve body composition
Benefits that are attributed to a ketogenic diet involve enhancing body composition. An athlete’s power-to-weight ratio is regarded as an indicator of performance, particularly in the case of cyclists. This ratio represents the amount of power an athlete can generate relative to their body weight. Essentially, the greater the power an athlete possesses for each kilogram of body weight, the higher their speed will be.
Research published in the journal Metabolism examined a group of endurance athletes who adhered to an identical training regimen for a duration of 12 weeks, as a means to enhance this ratio. Although shedding weight is one method to achieve this goal, there is a potential drawback of muscle loss, which ultimately hampers progress.
The participants were split into two categories: those who adhered to a ketogenic diet and those who followed a high carbohydrate diet. Results demonstrated that individuals on the ketogenic diet successfully lost 5.9kg of weight over a period of 12 weeks, while those on the high carbohydrate diet only experienced a 0.8kg loss.
Additionally, it was demonstrated that both groups preserved lean mass. Furthermore, enhancements in fat oxidation were observed, making this study one of the limited few to display improvements in particular performance outcomes.
Does the ketogenic diet help improve performance
Numerous studies have demonstrated that, when compared to a high carbohydrate diet, the ketogenic diet leads to higher rates of fat oxidation at higher percentages of VO2 max. VO2 max, a crucial metric of performance, indicates the maximum quantity of oxygen an athlete can utilize during physical exertion.
In highly trained endurance athletes, moderate-intensity exercise leads to maximum levels of fat oxidation, which occurs at around 59-64% of their VO2 max. Studies have demonstrated that the ketogenic diet can enhance fat metabolism beyond the typical VO2 max. Notably, one study found that athletes were able to improve their fat oxidation even when exercising at 70% of their VO2 max.
While fat oxidation may not be as reliable an indicator of performance as enhancements in VO2 max, race times, and time trials, there is insufficient research to confirm that the ketogenic diet enhances performance. However, the evidence supports the fact that a high carbohydrate diet yields more favorable results in improving performance outcomes.
The downsides of following the ketogenic diet
Maintaining the ketogenic diet is challenging due to the drastic dietary changes it requires, despite its attractiveness.
The diet is based on high-fat foods like meat, poultry, cheese, eggs, cream, avocado, oils, nuts, and seeds. It avoids all carbohydrate foods, such as grains, cereals, starchy vegetables like potatoes, and legumes including beans, pulses, and lentils.
Athletes who opt to adhere to this diet may find it beneficial to incorporate a daily multivitamin and mineral supplement, like Elite All Blacks Gold Multivitamin, due to the limitations imposed on consuming vegetables, which mainly consist of salad vegetables and greens, and fruits, which are primarily limited to berries in moderation.
Some athletes may find it challenging to prepare and plan keto meals. They may also dislike consuming a consistent amount of high-fat foods. Additionally, deviating even slightly from strict food intake can easily disrupt ketosis.
Followers of the keto diet must be cautious about consuming an excessive amount of meat, poultry, and fish, as they should focus on high-fat foods rather than high protein. This is because in the absence of carbohydrates, an excess of protein can be transformed into glucose within the body.
It is important to note that athletes may experience feelings of sluggishness and fatigue while adjusting to ketosis, which can have an impact on their training and performance. Based on research, it is crucial to keep in mind that it typically takes around 3-4 weeks to become fully adapted.
Periodized nutrition as a low carbohydrate approach
Periodized nutrition is a method that athletes can use to enhance exercise performance by promoting adaptations. ‘Training low’ is a technique of manipulating carbohydrate consumption to achieve these adaptations. This involves training with reduced glycogen availability, but it should not be confused with ketosis as it involves short-term carbohydrate depletion done periodically.
The objective of training low is to induce changes that enhance the metabolism of fats, consequently preserving glycogen reserves for crucial high-intensity racing segments. This dietary approach is also believed to stimulate the growth of mitochondria in cells that are responsible for producing energy within the body. AMP-activated protein kinase (AMPK), a vital protein involved in muscle adaptation, is speculated to be activated in the absence of glycogen.
Training low may aid in the promotion of similar adaptations in the body as endurance training. Various approaches have been suggested, incorporating:
- Twice-a-day training sessions that withhold carbohydrate intake between workouts
- Overnight fasting
- Prolonged training and restricting or postponing carbohydrate intake during sessions
- Delaying carbohydrate intake during recovery
You can incorporate this technique into your training session, beginning with a frequency of once per week. It is recommended to introduce it during low to moderate intensity sessions, allowing ample time for recovery before engaging in more intense sessions.
The evidence suggests that maintaining a higher intake of carbohydrates during high-intensity training is beneficial for enhancing performance and adaptation. Although it is possible to sustain performance on a ketogenic diet, the available research lacks sufficient proof of improved performance.
Endurance athletes can potentially experience performance benefits by incorporating a periodized diet, specifically by “training low,” which involves limiting carbohydrates in their diet at specific phases in their training schedule.
