It's a much slower and less efficient process than using glycogen stores though, so the energy isn't 'on tap' so to speak.
Wouldn't recommend it to anyone. I don't see why people can't simply lop 500 calories a day off their existing diet rather than go for such a dramatic cut. You'll lose a hell of a lot of lean muscle mass cutting calories so dramatically, which definitely isn't healthy. However, it seems that many people just want to lose 'weight' rather than fat, which is what they ought to be aiming for.
Thats actually incorrect, to an extent anyway. in ketosis you will burn far less muscle than on a "normal" diet because you stay in fat burning mode and you never leave fat burning mode. On a normal siple 500 less calorie diet you will always first burn carb's, your body doesn't instantly switch to fat only and the 2nd most available resourse after carbs is muscle, you will naturally burn muscle before fat burning kicks in and because you should be eating less calories each meal than you need before the next meal you will switch what energy you use each time and each time burn a little muscle.
The idea of ketosis is that you are always in fat burning mode, when you eat, you're still burning fat, when you don't you burn fat and theres never the switch/slow down that causes muscle to be used up in an emergency.
You need to realise, you will NEVER burn only 530calories, thats what you INTAKE, but your body has 3500calories available from each pound of fat you have. If you eat 530calories, your body is likely to burn between 1-2k calories a day of fat to compensate, theres entirely nothing wrong with that.
AS for lighter life being dangerous down to the OP's link. Firstly had she drunken that much water on ANY diet, including eating 2 pizza's a day and gaining weight, a normal healthy maintainance diet or eating whatever else she would have still died.
Every single point Lysander makes is factually incorrect, as has been said they tell you of the dangers of drinking to much water, they give you advice on how to eat a healthy diet aftewards and how to gradually change over, its all correct and fine advice but its all there.
She killed herself by drinking to much water theres really nothing else to say about it, she's a moron, a total moron.