The ketogenic diet has risen in popularity lately. It can be very useful, but it's important to keep in mind that it isn't a natural diet. As such, you should view it as a tool rather than a permanent way of eating. At its core, the keto diet is a hack. It tricks the body into thinking you're in starvation mode by restricting carbs. This is a stressor on the body that triggers several positive adaptations. The main benefit is that it improves insulin sensitivity which can help to correct the hormone imbalance caused by a carb-heavy, processed food diet.
You have to be careful, though, because tricking your body into thinking it's in starvation mode permanently has some negative side effects. Cortisol (the stress hormone) levels will typically rise. Most importantly, keto can lead to a hypothyroid condition - low T3 hormone production - which will lower metabolism. The thyroid damage can be permanent, so this is a real concern.
Once you are keto-adapted (ketone bodies over 0.5 mM with low and stable levels of insulin and blood glucose) it's a good idea to introduce some weekly days where carb intake is high. This will help to avoid the negative side effects I detailed above.
If you workout daily at a fairly high intensity (ahem... crossfitters), you can try an advanced technique that takes advantage of a certain biorythm. In the morning fat cells are more insulin sensitive, while muscle cells are more insulin sensitive in the evening - especially if you have depleted them of their glycogen via exercise. Therefore, keep your diet ketogenic during the day, but for dinner enjoy a serving of carbs. This hybrid approach allows you to benefit from daily periods of ketosis while still providing the swag you need for your daily workouts.