Ketogenic diet for the Endurance Athlete? December 11, 2019 – Posted in: Health is Wealth

A Ketogenic diet induces the release of ‘Ketones’ by the body (essentially by the liver) which are then used as a primary fuel instead of Glucose.

This happens by depriving the body of its primary fuel- glucose (from carbohydrates) and increasing the intake of fat. This deprivation makes the body think that it’s under starvation and the body starts breaking down fat for energy releasing Ketones.

A diet rich in carbs to provide fuel to sustain the high activity levels of an endurance athlete has been proven time and again. However, a Low-Carb Ketogenic Diet (LCKD) has recently gained popularity among endurance athletes and there are a few studies that study its effects as compared to the traditional high-carb diet on performance.

While the results of the studies have been mixed, it has been found that the two key factors that determine the effects on performance is the level of carbohydrate restriction and the length of the adaptation period, these factors also differentiate a LCKD from just a Low-Carb High-Fat Diet (LCHF).

NUTRITIONAL KETOSIS is key to a LCKD. If the athlete is on a LCHF diet without achieving ketosis then the physiological systems of the body are presented with a dilemma, since there is neither enough carbs or ketones to fuel the body. Which then leads to reduced performance and bonking.

To achieved ketosis & reap the benefits of the LCKD a diet the distribution of macros has been found to be- 80% of the Total Energy from Fats, 2g/kg body weight Protein intake and 35-40g of Carbs/day. The adaptation to this kind of diet is an extremely important factor that takes about 2-3 months.

In fact, researches that explored the effects of LCKD on endurance performance for a period of 21-30 days reported a decrease in performance, exercise efficiency and increased rates of perceived exertion.

LCKD compared to HC diet led to an increase in performance by 3 minutes in a 100 km time trial (while being high-intensity it was also long enough to challenge the fuel availability in the participants). An enhanced peak power output in a six-second sprint, and critical power test (CPT). All these results indicate a better power to weight ratio.

In conclusion, improved body composition, aerobic and anaerobic exercise responses are a result of the LCKD in endurance athletes (especially the ones struggling to maintain competitive race weight). Having said that, it is not a one size fits all situation, and a LCKD is certainly not the secret to success in endurance sports. While it may work for some it may not for the others. Thus, understanding how your body reacts to the change in diet is important which can come through an individualistic approach to diet prescription.