The keto diet is great to fuel cardiovascular exercise like jogging, cross-training or rowing. When doing low intensity exercise, such as walking, the fatty acids in the blood are used for energy. As you start to work harder (up to 60% of your maximum heart rate) fat from the body is used. This is because there is time to take this fat, combine it with oxygen and use it to fuel the activity. 

The keto diet is not so good when you need power. For example when weight lifting or sprinting. 

When you do weight lifting or exercises that need power, the muscles get damaged. It is only a small amount of damage to the muscle cells. However, due to this damage glycogen is blocked from being able to re-enter the muscles. This is a complicated process but it means that recovery is slower. 

Ketosis is where the body is using ketones from fat for energy. This happens once all the glycogen has been used up. Glycogen is the body’s emergency energy store in the liver and muscles. Normally glycogen would be used up during exercise. Afterwards it is restored from carbohydrates ready to be used the next time. 

Something else to bear in mind when eating a keto diet and exercising is what to do if you are going to be eating a big meal. The kind of meal you have for Thanksgiving or at Christmas. You don't want all your hard work to get undone. 

Firstly, fast for at least 12 hours before the meal – preferably 15/16. On the morning of the day you are having the meal, do a full body workout. Resistance work with weights is the best. Do about 4 sets of 20 for each part of your body. In other words make sure you exercise your legs, arms, chest, shoulders and back.