Could this be the end of carb-loading for endurance?

Coming to a supermarket shelf near you soon? Scientists have discovered that rather than sugary or fatty energy drinks, those containing ketones provide the most benefits to competitive cyclists.

Over the course of a half-hour ride, high level athletes were fed these fuels, most usually produced by the body when the liver is forced to break down fat stores for energy.

Lead author Pete J. Cox of the University of Oxford said that their production was "a natural response to energy crisis and is of vital importance to us as it allows us to survive 'insults' such as starvation and even the first few hours after birth when fuel levels are low.”

The athletes, who included former Olympians, who were given the drink with ketones in, were able to use the energy as muscle fuel. Additional benefits included less muscle soreness from lactate.

After the ketone drink, the cyclists traveled an average of 411 meters further in the half-hour time trial than after the carbohydrate drink, as reported in Cell Metabolism.

“It’s really interesting: with a single drink of nutritional ketone you can do the same exercise with completely different metabolism,” said Dr Cox.

“Given the findings of this study, that challenge our fundamental understanding of human physiology, it will be tempting for many to focus on pursuing the endurance and sport-related avenues, but it would be a great shame if the metabolic basis of this work was not further explored.”

The idea to develop a ketone food group came from the Defense Advanced Research Projects Agency (DARPA), the research branch of the United States army, who put out a $10 million call for the development of the most efficient food for soldiers to take onto a battlefield.  

One of the people to answer this call was University of Oxford biochemist, Professor Kieran Clarke.  With Dr Richard Veech at the National Institutes of Health, she assembled a team who invented the ketone ester drink, and this is the first efficacy study to show that the taking ketone can improve performance for certain types of activities. Safety studies have already been conducted and the drink does not have any adverse effects.

“Hopefully this finding will help many athletes realize that optimum fueling for sport is not simply to ingest as much carbohydrate as possible - before, during and after exercise,” said Timothy Noakes of the University of Cape Town in South Africa, who was not part of the new study, but advocates a low carbohydrate diet for health and weight loss.

“Currently the drink is not commercially available, and is difficult to make even in a laboratory (patent protected), meaning it may be some time before this drink, or ones like it can be made readily available to the public,” he told Reuters via email.

A University of Oxford spinout company, T∆S® Ltd, will now develop and commercialise the ketone drink.