Authors: Alicja Wypasek, Irene Molina-Gonzalez
The ketogenic diet has gained popularity due to its health benefits. However, many people adopt this diet without proper knowledge, relying on internet videos, blogs, and influencers who may not be qualified or have the required knowledge to recommend it. Any change in diet can have associated health risks. In this article, we spoke with Alicja Wypasek, a distinguished functional and lifestyle medicine nutritionist. With an MSc in Biochemistry and extensive experience working with athletes of all levels, Alicja is a trusted source of information. She’s also a professional handball player, seasoned runner, and certified personal trainer. We discussed with Alicja the benefits and risks of a ketogenic diet and important considerations when adopting this diet.
The foundation of a ketogenic diet
A ketogenic diet involves consuming a low amount of carbohydrates, which results in a metabolic state called ketosis. During ketosis, the body uses fat for energy instead of carbohydrates. When carbohydrate levels are very low, the liver produces ketones, which are utilised as an energy source [1].
Ketones may impact other mechanisms in the body, such as inflammation and oxidative stress [2, 3]. They can also contribute to producing new mitochondria and help manage certain conditions and diseases [2, 3]. Studies indicate that a ketogenic diet may have benefits for weight management, brain health, and reducing the frequency of seizures in epilepsy patients [3, 4]. It has also gained popularity among specific athletic groups, particularly in endurance sports, as it relies on fats for prolonged energy production [5]. Nonetheless, further research is necessary to fully understand all the mechanisms involved, and it is crucial to seek professional guidance when adopting this diet as it may not be suitable for everyone.
There are potential risks associated with a ketogenic diet, especially during the early stages of adaptation. Some individuals can experience side effects such as headaches, fatigue, and irritability, known as the “keto flu.” Other potential and more severe risks include kidney stress, loss of muscle mass, negative impacts on bone health, and cardiovascular dysfunction [6]. Therefore, it is crucial to stress the importance of professional monitoring when considering a ketogenic diet. This will help ensure the diet is safe and effective for each individual.
1. What should we consider when transitioning to a ketogenic diet, and how long should it take to see benefits?
(Alicja)
There are many points to consider, and due to people's physiology and adaptations, we cannot always see the benefits. A ketogenic diet may not suit everyone, particularly individuals with certain medical conditions, such as liver failure, pancreatitis, inborn disorders of fat metabolism, porphyria, and pyruvate kinase deficiency [7].
Firstly, ensure you are healthy enough to change your diet by consulting a professional, such as a sports nutritionist or dietician, who can provide personalised advice based on your health status and fitness goals. Advanced functional tests may also help personalise the diet plan by determining which fats to avoid or include.
Understanding a ketogenic diet's principles, potential benefits, and drawbacks is crucial before making an informed decision. What works for one person may not work for another, as factors such as metabolic rate, activity level, and overall health can influence your body's response.
Transition gradually to allow your body to adapt well. Start by reducing your carbohydrate intake while increasing healthy fats. Carbohydrate trackers like MyFitnessPal, Cronometer, or the Carb Manager app can be beneficial in minimising potential side effects and improving adherence.
Pay attention to nutrient intake, particularly electrolytes like sodium, potassium, and magnesium, which may need supplementation. Ensure you're consuming various nutrient-dense foods to meet your body's needs. Remember that fibre is essential for a healthy microbiome; eating colourful vegetables and fruits is a good source.
Achieving and maintaining ketosis requires strict adherence to carbohydrate restriction. Be mindful of hidden sources of carbs in foods and track your macros to stay within the ketogenic range. Maintaining ketosis may be difficult if you are busy and do not track your calories and food intake.
Prepare for potential side effects such as the "keto flu," which may include fatigue, headache, dizziness, nausea, vomiting, constipation, and low exercise tolerance. These symptoms typically lessen within a few days to weeks as your body adjusts to the low-carbohydrate, ketogenic state. In the first 30 days, you may also experience low energy, missed workouts, physical discomfort, cravings for sugary foods, and increased hunger. These experiences are common during the transition to a ketogenic diet and generally diminish as your body adapts.
2. Would different athletic populations (amateurs, elites, professionals) benefit differently?
(Alicja)
Yes, different athletic populations may experience varying benefits and challenges with a ketogenic diet:
Amateurs: Recreational athletes may benefit from improved endurance and fat metabolism but might face challenges during transition, including keto flu symptoms and cravings. Social factors and past eating disorders could also impact adherence.
Elites: Elite athletes with rigorous training schedules may find adapting to a ketogenic diet challenging due to the potential impact on training intensity and recovery. Transition time during the off-season is crucial, and they may prioritise performance gains over dietary experimentation.
Professionals: Professional athletes may approach a ketogenic diet cautiously, considering potential risks and benefits. With access to personalised meal plans and specialised supplements, they can better mitigate challenges and optimise their diet.
3. There is a lot of controversy and little evidence on whether ultramarathon runners would benefit from a ketogenic diet.
(Alicja)
Significant debate and limited conclusive evidence exist on whether ultramarathon runners would benefit from a ketogenic diet. Some studies and anecdotal reports suggest potential benefits in endurance and fat metabolism [5]. In contrast, others highlight possible drawbacks such as reduced high-intensity performance and difficulty maintaining the diet long-term [8] The effectiveness of a ketogenic diet for ultramarathon runners may depend on individual differences and specific training and racing contexts.
Endurance athletes may benefit as well from other types of diet outside ketogenic:
A high-carb diet for Endurance Training emphasises complex carbohydrates to sustain glycogen stores, providing reliable energy for extended workouts.
Balanced Macronutrient Diet for Endurance Training: This diet includes a mix of carbohydrates, proteins, and fats to support energy, muscle repair, and overall endurance.
Conclusions:
While ketosis offers promising advantages, such as enhanced fat metabolism and potential improvements in certain health conditions, its implementation requires careful consideration. Athletes, whether amateurs or professionals, must approach this diet cautiously, ensuring it aligns with their health status, training goals, and metabolic needs.
The ketogenic diet's efficacy in endurance sports remains a topic of debate, with varied outcomes reported among different athletic populations. Ultimately, personalised guidance from healthcare professionals and nutrition experts is crucial to navigating the complexities of the ketogenic diet safely and effectively in an athletic context.
REFERENCES
1. Zhu, H., et al., Ketogenic diet for human diseases: the underlying mechanisms and potential for clinical implementations. Signal Transduction and Targeted Therapy, 2022. 7(1): p. 11.
2. Dyńka, D., et al., The Ketogenic Diet and Cardiovascular Diseases. Nutrients, 2023. 15(15).
3. Dyńka, D., K. Kowalcze, and A. Paziewska, The Role of Ketogenic Diet in the Treatment of Neurological Diseases. Nutrients, 2022. 14(23).
4. Ruan, Y., et al., Ketogenic diet for epilepsy: an overview of systematic review and meta-analysis. Eur J Clin Nutr, 2022. 76(9): p. 1234-1244.
5. Costa, R.J.S., et al., Nutrition for Ultramarathon Running: Trail, Track, and Road. Int J Sport Nutr Exerc Metab, 2019. 29(2): p. 130-140.
6. O'Neill, B. and P. Raggi, The ketogenic diet: Pros and cons. Atherosclerosis, 2020. 292: p. 119-126.
7. Paoli, A., et al., Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. European Journal of Clinical Nutrition, 2013. 67(8): p. 789-796.
8. Stellingwerff, T., Competition Nutrition Practices of Elite Ultramarathon Runners. International Journal of Sport Nutrition and Exercise Metabolism, 2016. 26(1): p. 93-99.
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