Ketosis is a normal body reaction to low blood sugar -- whether you induce it by a low-carb diet, whether you forget to eat and have low blood sugar, or especially if you've ever gone on a starvation diet, you've been in ketosis before.

Now the fly in the ointment is that when you have low blood sugar and ketosis, you are usually a little disoriented, lightheaded, or have inability to concentrate well. This is less pronounced when you are eating enough dietary protein and fat than when you are on a starvation diet.