Fueling Performance: Ketones Enter the Mix
Ketone body metabolites serve as alternative energy substrates during prolonged fasting, calorie restriction, or reduced carbohydrate (CHO) availability. Using a ketone ester supplement, Cox et al. (2016) demonstrate that acute nutritional ketosis alters substrate utilization patterns during exercise, reduces lactate production, and improves time-trial performance in elite cyclists.
Ketone drink gives competitive cyclists a boost by altering their metabolism
A drink developed for soldiers to generate energy from ketones rather than carbs or fat allowed highly trained cyclists to add up to 400 meters of distance to their workouts, an Oxford-led study has reported in journal Cell Metabolism. The supplement, which will be commercially available within the year, works by temporarily switching the primary source of cellular energy from glucose or fat to ketones – molecules derived from fat that are known to be elevated in people consuming a low-carb, Atkins-like, diet.
‘It’s really interesting: with a single drink of nutritional ketone you can do the same exercise with completely different metabolism,’ said Dr Pete Cox, a clinician at the University of Oxford and first author on the paper. ‘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.
In a study of 39 cyclists, some former Olympians, the team found that the muscles use ketones when provided in the diet, and that this uptake increases in proportion to the intensity of exercise. In one experiment, the researchers gave the cyclists ‘energy drinks,’ each infused with a different source of fuel – carbohydrates, fats, or ketones – and found that cyclists who had the ketone drink had the lowest levels of lactate, a byproduct of the body’s breakdown of glucose, which is often associated with muscular stress, or the achy, tired feeling felt after a strenuous workout. The observation could help explain why the high-performing cyclists on the ketone drink travelled an average of 400 meters further over a half hour than those consuming the carbohydrate or fat drink.
Nutritional Ketosis Alters Fuel Preference and Thereby Endurance Performance in Athletes
•Nutritional ketone bodies can promote the advantageous aspects to starvation ketosis
•Nutritional ketosis alters the hierarchy of substrate competition for respiration in exercise
•Ketosis increases metabolic flexibility during exercise, reducing glycolysis and increasing muscle fat oxidation
•Improved performance during cycling time trial suggests ketosis during exercise may be beneficial for some athletes
Ketosis, the metabolic response to energy crisis, is a mechanism to sustain life by altering oxidative fuel selection. Often overlooked for its metabolic potential, ketosis is poorly understood outside of starvation or diabetic crisis. Thus, we studied the biochemical advantages of ketosis in humans using a ketone ester-based form of nutrition without the unwanted milieu of endogenous ketone body production by caloric or carbohydrate restriction. In five separate studies of 39 high-performance athletes, we show how this unique metabolic state improves physical endurance by altering fuel competition for oxidative respiration. Ketosis decreased muscle glycolysis and plasma lactate concentrations, while providing an alternative substrate for oxidative phosphorylation. Ketosis increased intramuscular triacylglycerol oxidation during exercise, even in the presence of normal muscle glycogen, co-ingested carbohydrate and elevated insulin. These findings may hold clues to greater human potential and a better understanding of fuel metabolism in health and disease.
Jeff S. Volek, Ph.D., R.D.
Dr. Jeff Volek is a Professor in the Department of Human Sciences at The Ohio State University. A world-renowned expert in low carbohydrate research, Dr. Volek focuses on the clinical application of ketogenic diets, especially the management of insulin resistance and type-2 diabetes, as well as athletic performance and recovery. His research aims to understand individual variability including how ketogenic diets alter fatty acid composition, lipoprotein metabolism, gut microbiome, gene expression, adaptations to training and overall metabolic health. He has performed several prospective diet studies that demonstrate that well-formulated ketogenic diets result in substantial improvements in (if not complete reversal of) metabolic syndrome and type-2 diabetes. Dr. Volek has garnered over $7 million in research grants over the last 15 years, and accumulated an enormous amount of laboratory and clinical data as it pertains to biomarker discovery and formulation of personalized, effective and sustainable low carbohydrate diets. In addition to research, Dr. Volek has several initiatives aimed at translating low-carbohydrate science to the public including his role as Chief Scientist of KetoThrive Corp. He has also performed seminal work on dietary supplements including creatine, carnitine, and whey protein. He has been invited to lecture on his research more than 150 times at scientific and industry conferences in eight countries. His scholarly work includes 280 peer-reviewed scientific manuscripts and 5 books, including a New York Times Best Seller, collectively selling over 700 hundred thousand copies.
Metabolic characteristics of keto-adapted ultra-endurance runners
Many successful ultra-endurance athletes have switched from a high-carbohydrate to a low-carbohydrate diet, but they have not previously been studied to determine the extent of metabolic adaptations.
Twenty elite ultra-marathoners and ironman distance triathletes performed a maximal graded exercise test and a 180 min submaximal run at 64% VO2max on a treadmill to determine metabolic responses. One group habitually consumed a traditional high-carbohydrate (HC: n = 10, %carbohydrate:protein:fat = 59:14:25) diet, and the other a low-carbohydrate (LC; n = 10, 10:19:70) diet for an average of 20 months (range 9 to 36 months).
Peak fat oxidation was 2.3-fold higher in the LC group (1.54 ± 0.18 vs 0.67 ± 0.14 g/min; P = 0.000) and it occurred at a higher percentage of VO2max (70.3 ± 6.3 vs 54.9 ± 7.8%; P = 0.000). Mean fat oxidation during submaximal exercise was 59% higher in the LC group (1.21 ± 0.02 vs 0.76 ± 0.11 g/min; P = 0.000) corresponding to a greater relative contribution of fat (88 ± 2 vs 56 ± 8%; P = 0.000). Despite these marked differences in fuel use between LC and HC athletes, there were no significant differences in resting muscle glycogen and the level of depletion after 180 min of running (- 64% from pre-exercise) and 120 min of recovery (- 36% from pre-exercise).
Compared to highly trained ultra-endurance athletes consuming an HC diet, long-term keto-adaptation results in extraordinarily high rates of fat oxidation, whereas muscle glycogen utilization and repletion patterns during and after a 3 hour run are similar.
Fat Adaptation: The Emerging Science from FASTER
Like the Bob Dylan song, there is a “change is coming on” in sports physiology. A small but growing group of Ultrarunners & Triathletes have been actively pursuing a fat-adapted approach with success, including some of the elite athletes, most notably ultra-runners Zach Bitter, Jon Olsen, Jenny Capel and Nikki Kimball along with triathletes Triathetes Amanda Stevens, Rodrigo Gonzales, Nell Stephenson and Jess Anderson. Fat adaptation involves sharp carbohydrate restriction in conjunction with a complementing increase in fat consumption (with many of those fats being saturated fats) to induce the physiological shift necessary for the body to “switch” to burning “fat as fuel” at much higher rates. The various terms for this can be “Ketosis”, “Keto-adapted”, “fat-adapted”, “Nutritional Ketosis”. In conjunction with the dietary shift specific training, both in low and high intensity is programmed into the training blocks to push the fat burning envelope into higher intensity levels.
Observationally, athletes following this approach have been able to complete ultra-endurance races on a fraction of the caloric intake normally necessary, many athletes report completing 100 Mile runs or sub-10 hour IM Triathlon on 600-2000 calories. Unfortunately, there is scant science to support the plausibility of such a dramatic drop in consumption. That is, until now. In 2013 Dr. Jeff Volek RD/PhD, his graduate students and colleagues commenced data collection for the FASTER Study (FASTER=Fat-Adapted-Substrate oxidation in-Trained-Elite-Runners) to look at the physiological differences between elite male ultra-marathon runners with one cohort following a conventional high carbohydrate diet and the other following a low carb/fat-adapted strategy.
On November 2, 2015 the first paper from FASTER submitted for Peer-review publication in the Journal “Metabolism” was approved for publication. This ground-breaking study used two cohorts of ultrarunners (runners who regularly compete and train in events beyond the marathon distance of 26.2 miles). From the chart below these two cohorts, High Carb Conventional Diet & Low Carb Fat-Adapted Diet, were very well matched.
The Performance Benefits of Being Keto-Adapted
By Michael Joseph, MSc – July 11, 2017