Keto And Marathons: Does This Diet Really Work?

The ketogenic diet is a high-fat, low-carb nutrition plan that gets you into ketosis: a metabolic state in which your body taps into fat as a primary energy source instead of carbohydrates. Reaching ketosis is challenging as it requires limiting your daily carb intake to 20-30 grams. This means cutting out sugar, grains, starches, root vegetables, tubers, and most fruits.

The keto diet is popular for its health benefits, including lowering the risk of heart disease, certain cancers, and epilepsy. It is also touted as a weight-loss solution. However, the keto diet is controversial among runners as it goes against the conventional wisdom that carbohydrates are integral to a runner's diet.

Some elite athletes, like ultra-marathoner Zach Bitter, have had success running on a keto diet. Bitter, who is the 100-mile American record holder, attributes his success to being fat-adapted, meaning his body is used to burning fat instead of carbs for fuel. He does note, however, that it took time for his body to adjust to the keto diet, and his performance suffered initially.

If you're considering trying the keto diet, be aware that it can take months to become fully fat-adapted, and your performance may suffer in the meantime. It's also important to ensure you're consuming enough calories and healthy fats to fuel your body. Some runners on the keto diet also practice carb cycling, where they consume more carbs on heavy training days.

In conclusion, while it is possible to run a marathon on a keto diet, it may not be the best approach for everyone. It requires a significant adjustment for your body and may not lead to the performance improvements you desire.

The basics of keto running

The keto diet is a high-fat, low-carb nutrition plan that gets you into ketosis: a metabolic state in which your body taps into fat as a primary energy source instead of carbohydrates (glycogen). To reach ketosis, you'll need to limit your carbohydrate intake to 5-10% of your total daily calories (or 25-35 grams of carbs a day) and increase your fat intake to 75% of your total calories. This typically means eating lots of healthy fats, moderate protein, and almost no carbs.

When running long distances, a runner's body first uses stored carbohydrates (glycogen) as fuel. The keto diet aims to change this by forcing the body to burn fat as its primary fuel source instead. This means that, in theory, runners can access a more copious fuel source: body fat. Research estimates that body fat contains around 20 times more calories than glycogen, even in a lean person.

Who is keto running suitable for?

Keto running may be beneficial for ultra-runners, as they tend to run at a slower and steadier pace than other runners. The more intense the race, the more you'll need carbohydrates instead of fat for fuel. It's also important to note that keto running may not be suitable for everyone, and it can take months to become fully fat-adapted. Additionally, some athletes never seem to fully adapt to fuelling for endurance training while eating keto.

How to get started with keto running

If you want to try keto running, it's important to do it the right way. Here are some tips to get you started:

• Make sure you've been in ketosis for a while. It can be hard to find the energy for distance running at your pre-keto pace if you're new to keto.
• Eat the right foods. Your diet should be high in healthy fats, such as avocado, nuts, butter, nut butters, chia seeds, hemp hearts, and olives. Avoid grains, starches, processed foods, sugary foods and drinks, and low-fat products.
• Consider carb cycling. This involves consuming a higher number of low-glycemic index carbs, such as sweet potatoes or quinoa, on heavy training days to ensure you have enough fuel.
• Fuel during runs. If you need to take in fuel while running, options include small packs of nut butter or pouches of seeds like sunflower seeds. You can also drink smoothies made with keto-friendly berries, avocado, flax, and unsweetened almond milk.

The pros and cons of a keto diet

The keto diet is a high-fat, low-carbohydrate diet that has gained popularity in recent years, especially among those looking to lose weight. The diet typically consists of 55-60% fats, 20% protein, and 5-10% carbohydrates. While the keto diet has been touted as an effective weight loss tool, there are both pros and cons to consider before adopting this dietary approach.

Pros:

• Weight Loss: The keto diet can lead to rapid weight loss, especially in individuals with a significant amount of excess body weight. This is due to the reduction in water weight and the appetite-suppressing effects of ketones.
• Blood Sugar Management: The keto diet has been shown to help stabilise blood sugar levels, making it beneficial for people with type 2 diabetes.
• Potential Cancer Treatment: Some small studies suggest that the keto diet may ''starve' cancer cells of energy, potentially weakening them and making them more susceptible to chemotherapy and radiation.
• Improved Fat Adaptation: The keto diet can improve fat adaptation, which is beneficial for endurance athletes as it allows them to utilise fat as a fuel source during long-duration exercises.
• Increased Satiety: The keto diet may lead to increased feelings of fullness and reduced hunger between meals due to the satiating effects of fatty foods.

Cons:

• Nutrient Deficiencies: The keto diet restricts fruits, vegetables, and other nutrient-rich foods, leading to potential deficiencies in vitamins, minerals, and fibre.
• Digestive Issues: The low fibre content of the keto diet may cause constipation and other digestive issues.
• Negative Impact on Heart Health: The high-fat nature of the keto diet, especially the consumption of saturated fats, can increase the risk of heart disease by raising levels of LDL (bad) cholesterol.
• Difficult to Sustain: The restrictive nature of the keto diet makes it challenging to stick to and can lead to yo-yo dieting, which is associated with increased mortality.
• Social and Practical Challenges: The keto diet can be difficult to maintain in social settings and may require significant meal planning and food preparation.
• Lack of Long-Term Research: There is a lack of long-term data on the safety and effectiveness of the keto diet.

How to train for a marathon on keto

Training for a marathon on a keto diet is possible, but it takes careful planning and time to adjust to a new way of fuelling your body. Here are some tips on how to train for a marathon while following a ketogenic diet.

Understanding Keto

First, let's understand what keto is and how it works. The keto (short for ketogenic) diet is a way of eating that aims to make your body very efficient at burning fat for energy instead of carbohydrates, which are the primary source of energy for most people. On keto, you drastically reduce your carbohydrate intake (to around 5-10% of your total daily calories or 25-35 grams per day) and increase your fat intake (up to 75% of your total calories). This shift forces your body to enter a state called "ketosis", where it starts burning fat as its main fuel source.

The Benefits of Keto for Runners

So, why would a runner want to follow a keto diet? Well, for one, it can provide a more stable and long-lasting energy source. Once your body becomes "fat-adapted", you may experience fewer energy spikes and crashes throughout the day, and you may find that you can run for longer periods without needing to refuel. This is because your body can store about 20 times more fat calories than carbohydrates, giving you an almost infinite energy supply. Additionally, keto can lead to improved mental clarity and better overall health, with potential benefits for heart health, brain health, and even a reduced risk of certain cancers.

The Challenges of Keto for Runners

Now, for the cons. The biggest challenge of keto for runners is the initial adaptation period. When you first switch to keto, your body will be used to relying on carbohydrates for fuel, and it will take time to adjust to burning fat primarily. This means you may experience a decrease in performance and energy levels during the first few weeks or even months of keto. It can be tricky to time this adaptation period with your marathon training plan, and you may need to lower your expectations for your training pace and distance during this time. Additionally, keto requires a lot of discipline and planning, as it can be easy to accidentally consume too many carbohydrates and knock yourself out of ketosis. Social situations can also become more complicated, as you'll need to be very mindful of what you're eating and drinking.

Practical Tips for Keto Marathon Training

Now, let's get into some practical tips for training for a marathon while on keto:

• Give yourself time to adapt: It can take months to become fully fat-adapted, so don't rush the process. Start keto during your off-season or well before you begin training for a specific race. This will give your body time to adjust to burning fat for fuel and reduce the risk of negative side effects during the adaptation period.
• Experiment with carb cycling: Some keto athletes find success with carb cycling, where you strategically increase your carbohydrate intake on heavy training days. This can give you the boost you need for long runs or challenging workouts while still keeping you in ketosis overall. Focus on high-quality, real food carbs like sweet potatoes or quinoa.
• Find keto-friendly fuel sources: If you're used to fuelling with sports gels, you'll need to find keto-friendly alternatives. Options include nut butters in small packs, seeds like sunflower seeds, or smoothies made with keto-friendly berries, avocado, flax, and unsweetened almond milk.
• Be mindful of your fat intake: Remember, fat is your primary fuel source on keto, so make sure you're consuming enough healthy fats like avocado, nuts, butter, nut butters, olive oil, and chia seeds.
• Plan your meals: Stock your kitchen with keto-friendly foods and plan your meals ahead of time to ensure you stay on track. Focus on healthy fats, moderate protein, and very few carbs.
• Be patient: Finally, be patient with yourself and the process. It takes time for your body to adjust to a new way of fuelling, and you may experience ups and downs along the way. Give yourself at least a few months to see how your body adapts and whether keto is a sustainable diet for you.

In conclusion, it is possible to train for a marathon while following a ketogenic diet, but it requires careful planning and time to adjust. The benefits of keto for runners include improved fat adaptation, stable energy levels, and potential overall health benefits. However, the challenges include a difficult initial adaptation period and the need for discipline and planning. If you're considering keto for marathon training, give yourself plenty of time to adjust, experiment with different fuelling strategies, and be patient as your body learns to burn fat for fuel.

What to eat during marathon keto

The keto diet is a popular choice for those looking to improve their health and energy levels, but it is often looked down upon by long-distance runners and coaches due to its potential negative impact on performance. However, some endurance athletes have found success with keto, and it can be rewarding for those willing to put in the work.

Full Ketosis Takes Time

Transitioning to keto can take weeks or even months, and it is important to be patient during this period. You will likely experience low energy and increased hunger as your body adjusts to using fat instead of carbohydrates as its primary fuel source. It is recommended to start a keto diet during the off-season when running intensity and volume are lower to minimize the impact on training.

Electrolytes and Protein

One common mistake is forgetting about electrolytes, as they are usually obtained from carbohydrate-rich foods. You can take salt pills or dissolve a bouillon cube in hot water to make a salty drink and ensure adequate electrolyte intake. Additionally, consuming protein after runs is crucial for muscle recovery, and protein shakes are a fast and easy way to meet your protein needs.

Snacks and Meals

Most snacks and gels designed for runners are high in simple sugars, which can throw you out of ketosis. Making your own snacks like frozen peanut butter balls, dark chocolate, and cheese sticks is recommended. For meals, focus on fatty foods and protein, such as steak, salmon, bacon, eggs, avocado, nuts, and nut butters.

Breakfast and Energy Levels

Breakfast is essential when training for a marathon on keto. Eating a big breakfast will provide your body with fat and protein to burn throughout the day, helping to maintain energy levels. However, if running in the morning causes cramps, consider having a few calorie-dense snacks during your run and a big breakfast afterward.

Low-Energy Days and Interval Training

Even with proper fueling and recovery, low-energy days will occur, and it is important to adjust your workouts accordingly. Interval training can be challenging on keto, and it is recommended to limit it to once a week at most.

Carbohydrate Intake and Performance

Small amounts of carbohydrates are acceptable on keto and can be strategically consumed around runs to provide an energy boost. However, it is important to note that carbohydrates are better than fats for fueling long-distance sports, and keto may negatively impact your speed and performance.

Social Considerations

Keto can be restrictive and impact your social life, especially when dining out or socializing with friends and family. It requires discipline and consistency to maintain ketosis, and you may need to make sacrifices or skip social meals to stay on track.

In summary, marathon keto requires careful planning and adjustments to your diet and training regimen. It may take several weeks or months to adapt fully, and it is important to be patient during this transition period. While keto can offer benefits such as improved energy levels and fat adaptation, it may also negatively impact your running performance, especially when it comes to speed.

Research on keto and endurance performance training

The ketogenic diet has become popular among endurance athletes as a performance enhancer. However, the evidence is mixed, and more research is needed to understand the effects of a ketogenic diet on endurance performance.

Ketogenic diet and endurance performance

The ketogenic diet (or keto) is a low-carb, high-fat diet that aims to make the body more efficient at using fat as its primary energy source. This is achieved by reducing carbohydrate intake to 5-10% of total daily calories (or 25-35 grams of carbs per day) and increasing fat intake to up to 75% of total calories. This shift in macronutrient ratios forces the body to enter a state of ketosis, where it burns fat as its main fuel source.

Keto has been shown to provide a consistent and fast energy supply, improve exercise performance and capacity, and contribute to muscle health by reducing inflammation and oxidative stress. These effects may be particularly beneficial for endurance athletes, who rely on sustained energy levels and recovery.

Research findings on keto and endurance performance

Some studies have found that keto can enhance endurance performance and body composition in athletes. For example, one study reported that keto-adapted ultra-endurance runners had a 2.3-fold higher peak fat oxidation rate compared to non-adapted athletes. Another study found that a ketogenic diet improved exhaustive cycling performance and increased fat oxidation capacity.

However, other studies have found no significant improvements or even negative effects on endurance performance with keto. For example, one study reported that a ketogenic diet impaired exercise economy and performance in elite race walkers, while another study found no significant changes in maximal oxygen consumption (VO2 max) or other performance outcomes in keto-adapted endurance athletes.

Limitations and future research

The mixed findings on the effects of keto on endurance performance may be due to individual differences in genetic factors, training protocols, and other variables. Additionally, most of the existing studies have small sample sizes and are not randomized controlled trials, which limits their ability to draw definitive conclusions.

More high-quality research is needed to understand the effects of keto on endurance performance, including the impact of genetics, recovery, sport type, and sex. Future studies should also consider the potential benefits of keto-like diets that do not induce full ketosis, as well as the combination of keto with other nutritional strategies or supplements.

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