This article reviews some of the ways that the ketogenic diet could affect your workout.

While some claim that keto can boost fat burning and enhance endurance, others note that it could drain energy levels and make muscle growth more challenging.

However, its effect on athletic performance remains a subject of controversy.

The very low carb, high fat, moderate protein ketogenic diet has been linked to a long list of potential health benefits, ranging from improved blood sugar control to decreased hunger levels ( 1 , 2 ).

Studies show that the ketogenic diet may improve several aspects of athletic performance.

May improve endurance

Although the ketogenic diet may not be suitable for high intensity bursts of activity, some studies have found that it may enhance performance for endurance athletes.

For example, one study in 39 athletes noted that being in a metabolic state of ketosis improved physical endurance due to the body’s ability to use fat as an alternative source of energy ( 3 ).

However, this was observed in the context of providing ketone supplements — not through following the ketogenic diet.

Another study in 20 endurance athletes had similar findings, reporting that following a ketogenic diet for 12 weeks improved performance, body composition, and fat burning during exercise ( 4 ).

What’s more, one review reported that increased levels of ketone bodies from supplements may speed muscle recovery and reduce the breakdown of protein following endurance exercise ( 5 ).

On the other hand, some research has found that it could negatively affect performance in endurance athletes by impairing energy utilization and speeding time to exhaustion ( 6 , 7 ).

Therefore, more studies are needed to determine whether the ketogenic diet offers any added benefits over other diets for endurance athletes.

May boost fat burning

Some research indicates that following a ketogenic diet may help boost fat burning during exercise.

In fact, one small study in competitive race walkers showed that the diet increased the body’s ability to burn fat while working out, even during a range of different intensities of physical activity ( 6 ).

However, the ketogenic diet ultimately impaired exercise performance in these athletes.

Another study in 22 athletes found that switching to a ketogenic diet increased fat burning over a 4-week period ( 8 ).

Of course, it’s important to keep in mind that the ketogenic diet comprises mostly fat, which may explain why more fat is burned during exercise.

Additionally, note that fat contains a significantly higher number of calories per gram than carbs or protein (9).

Therefore, just like any other diet, creating a calorie deficit by adjusting your intake to consume fewer calories than you burn is still necessary if you’re looking to lose weight on the ketogenic diet ( 10 ).

Can speed muscle recovery

Several studies have found that the ketogenic diet could help speed up post-workout muscle recovery.

For instance, one small study reported that the ketogenic diet led to self-perceived improvements in recovery and inflammation after exercise in five athletes ( 7 ).

However, it’s important to note that they also experienced reductions in other measures of performance, and there was no control group, which could skew results ( 7 ).

Another study in off-road cyclists noted that the ketogenic diet reduced levels of creatine kinase and lactate dehydrogenase — two enzymes used to measure muscle damage ( 11 ).

Furthermore, a mouse study showed that following a ketogenic diet for 8 weeks increased muscle recovery following exhaustive exercise ( 12 ).