Do Ketone Drinks Improve Performance?
If you’ve been paying attention to pro cycling, you’ve likely heard the hype surrounding ketones. Back in July 2019 during the Tour de France, news broke that WorldTour Teams like Jumbo-Visma, Lotto-Soudal and Deceuninck-Quickstep were using ketone ester (KE) drinks to aid performance.
Before you knew it, KE supplementation was exploding in the media as a performance aid. Although the strategy was first introduced into UK sports as early as the 2012 Olympics, the revelation that WorldTour teams were using KEs in this year’s TDF with seemingly great success reignited the conversation.
But what exactly are ketone drinks and how might they be beneficial to athletic performance?
What are Ketones?
Ketones or ketone bodies are produced in the liver from the breakdown of fat and used for energy when glucose is not available. Ketones provide alternative fuel for the body when glucose is in short supply, for instance when the body is fasting or undertaking a low-carbohydrate, high-fat ketogenic diet.
In addition to their role in energy supply, ketone bodies can also play a part in metabolic regulation by inhibiting muscle protein breakdown and glucose depletion, as well as help stimulate muscle regeneration.
Ketosis and Exercise Performance
At face value, this sounds highly desirable for athletes. If we compel the body to predominantly break down fat for fuel, we can preserve finite glycogen (stored carbohydrates) reserves — a common limiter in performance, and curb muscle protein breakdown.
However, it is well-documented that the dietary conditions required to elevate blood ketone levels via a sustained low-carb/high-fat diet are detrimental to exercise performance. Why? Because the reduced consumption of carbohydrates required to get into a state of ketosis denies the body of the most important macronutrient in sustained exercise performance: carbohydrates. It is only at very low levels of exertion that carbohydrates are not the primary fuel source.
The Work-Around: Ketone Ester Drinks
KEs are a dietary supplement best described as “ketosis in a drink.” They are a form of exogenous ketones that put your body into a state of ketosis without having to adopt the carb-restricted ketogenic diet.
There are two lines of thinking when it comes to KE supplementation and athletic performance.
The first theory is that it helps to spare glycogen (i.e. you can go harder for longer) and improves glycogen resynthesis after exercise, boosting future performances.
The second theory considers KE consumption after exercise as a solution to improve recovery and help prevent symptoms of over-reaching and/or over-training
But when it comes to these claims on athletic performance, the strength of evidence is still quite low.
Does Ketone Ester Supplementation Spare Glycogen?
One theory suggests that KE supplementation helps stimulate muscle glycogen resynthesis after exercise, however multiple studies have contradicted this hypothesis stating that if the athlete consumes sufficient amounts of carbohydrates and protein post-exercise, the addition of ketones does not further stimulate glycogen resynthesis.
Other studies have suggested that KE consumption during exercise spares glycogen, however other studies have not been able to confirm this benefit.
A major concern with consuming KE during exercise lies in the fact that KEs are acidic and have a substantial effect on pH regulation. They produce mild, systemic acidosis in the body which negatively impacts muscle function and capacity, as well as hinders aerobic and anaerobic metabolism.
Can Ketone Ester Supplementation Improve Recovery?
This year, Leuven University physiologist and ketone research pioneer Peter Hespel published a study presenting strong evidence that KE supplementation after exercise has the potential to improve endurance performance by stimulating recovery.
The study launched KE supplementation back into the public spotlight.
Caveat: Hespel’s study specifically researched the effects of ketone ester supplementation during an extended endurance training overload period (similar to that of the Tour de France) where the athlete enters an extreme and continuous catabolic state.
Potential Ketone Ester Supplementation Benefits:
- High potential to increase endurance performance up to 16%
- Substantial stimulation of protein synthesis in the muscle
- Increased potential to manage higher training loads
- Higher power output at the end of a workout after 3 weeks of overload training
- Suppressed heart rate drop during exercise, suggesting fatigue resistance
- Improved sleep efficiency
Unknowns of Ketone Ester Supplementation
- Long term effects on the body and metabolism
- Length of time ketone esters will continue to be effective
- Potential to inhibit beneficial training adaptations as the body is being given assistance in its natural recovery process
- Optimal timing for usage
- Prohibitively expensive
The Bottom Line
Do ketone drinks improve performance? Maybe
Although there are some promising signs, research is still inconclusive in showing KEs as a beneficial performance aid. While successful professional athletes are certainly using them, others are choosing not to. In time, we should have more answers.
At the end of the day, don’t lose sight of what matters most when it comes to endurance performance. While ketone supplementation is currently a hot topic, its potential benefits would represent only marginal gains. What we know for certain is that nailing your fueling and hydration strategies will make the most significant impact on your overall performance.
What are your thoughts on supplementing with ketones? Let us know!
Ketone ester supplementation is FDA approved and is not currently considered to be doping by the World Anti-Doping Agency.
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