It entirely depends on your goals. For athletes who cycle through different phases of training, you can adopt the ketogenic diet into the base phase (lower intensity, lower workload) of your training cycle. During base phase, for example, this is the perfect opportunity to enhance your ability to burn fat, improve body composition and your ability to go longer. However, in the key phase of improving speed and performance, it is more appropriate to fuel with carbohydrate. This same approach can be adopted for team-based athletes during their off season.