Will Adding Ketones to Your Pre-Workout Increase Performance and Enhance Fat Burning?

Will Adding Ketones to Your Pre-Workout Increase Performance and Enhance Fat Burning?

Athletes are constantly looking for new supplements to increase performance in the gym and on the field. There is a long list of supplements that have been proven to increase performance such as creatine, beta-alanine, caffeine, HMB, etc. The latest trend in sports is to add ketones to a pre-workout drink if you are on a low-carb diet to enhance performance. Physiologically, it makes sense to add ketones to a pre-workout to enhance performance as ketone bodies can serve as an alternative fuel for the brain and ketone bodies have been suggested to enhance performance in endurance athletes. It is suggested that ketone body supplementation during exercise enhances fat oxidation as a result of this enhancing performance and fat burning. Lifters may think this is something new, but studies examining the use of adding ketones to the body thru ketone salts and intravenous ketones have been conducted in the 1960’s.

How Ketones Work in the Body
Ketone bodies can serve as an important energy substrate under certain conditions, such as starvation, and can spare carbohydrates and increase fat metabolism. The effects of ketones depend on upon the depletion of hepatic and muscle glycogen reserves, thereby increasing circulating free fatty acids and endogenous ketone body production. Ketones are increased on a low carbohydrate diet. Dietary strategies to increase endogenous ketone body availability (i.e., a ketogenic diet) require a diet high in lipids and low in carbohydrates for to induce nutritional ketosis. Most bodybuilders will consume a ketogenic diet while dieting for a show in which is characterized by high fat, low carbohydrate, and high intake. However, the level of ketonemia induced via a ketogenic diet is largely dependent on the amount of carbohydrate ingested, and low much liver and muscle glycogen stores have been depleted.

Do Increased Ketones via Supplementation Increase Fat Oxidation during Exercise?
This may be shocking to some people, but previous research has shown that ketone bodies have also been shown to reduce circulatory free fatty acid availability via inhibiting the lipolytic effect of catecholamines, and/or via stimulation of hyperinsulinemia, which subsequently reduces lipolysis. One study reported, at low ketonemia, exercise stimulates the metabolic clearance of ketones, which indicates that working muscles have an increased capacity to extract ketones from blood compared to resting muscle. As ketonemia rises with persistent fasting, this effect of exercise on the metabolic clearance rate is progressively reduced, and it is completely abolished when basal plasma ketone body levels exceed 3-4 mmol/L. The well known lipolytic effect of exercise (which would tend to stimulate ketogenesis) was almost totally suppressed despite a significant decrease in plasma insulin levels; this phenomenon probably is related to the antilipolytic effects of the infused ketones

A landmark study by Fery and Balasse reported that the intravenous administration of ketone bodies during exercise suppressed the exercise-mediated increase in circulating FFA and glycerol availability, suggesting that ketone bodies may have suppressed the lipolytic effect of exercise.

In conclusion, based upon the few available data and our current understanding of ketone body metabolism during exercise in a sports specific setting, the researchers conclude there is currently no evidence to support the use of ketone bodies as an ergogenic aid under conditions where optimal evidence-based nutritional strategies are applied.

Ketone Bodies and Exercise Performance: The Next Magic Bullet or Merely Hype? Sports Med. 2016 Jul 18.

Abstract
Elite athletes and coaches are in a constant search for training methods and nutritional strategies to support training and recovery efforts that may ultimately maximize athletes’ performance. Recently, there has been a re-emerging interest in the role of ketone bodies in exercise metabolism, with considerable media speculation about ketone body supplements being routinely used by professional cyclists. Ketone bodies can serve as an important energy substrate under certain conditions, such as starvation, and can modulate carbohydrate and lipid metabolism. Dietary strategies to increase endogenous ketone body availability (i.e., a ketogenic diet) require a diet high in lipids and low in carbohydrates for 4 days to induce nutritional ketosis. However, a high fat, low carbohydrate ketogenic diet may impair exercise performance via reducing the capacity to utilize carbohydrate, which forms a key fuel source for skeletal muscle during intense endurance-type exercise. Recently, ketone body supplements (ketone salts and esters) have emerged and may be used to rapidly increase ketone body availability, without the need to first adapt to a ketogenic diet. However, the extent to which ketone bodies regulate skeletal muscle bioenergetics and substrate metabolism during prolonged endurance-type exercise of varying intensity and duration remains unknown. Therefore, at present there are no data available to suggest that ingestion of ketone bodies during exercise improves athletes’ performance under conditions where evidence-based nutritional strategies are applied appropriately.

Pinckaers PJ, Churchward-Venne TA, Bailey D, van Loon LJ. Ketone Bodies and Exercise Performance: The Next Magic Bullet or Merely Hype? Sports Med. 2016 Jul 18.

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Madison LL, Mebane D, Unger RH, et al. The hypoglycemic action of ketones. II. Evidence for a stimulatory feedback of ketones on the pancreatic beta cells. J Clin Invest. 1964;43(3):408–15.

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