Calorie restriction is supposed to be healthy and I would agree to a point it is. I would have tens of thousands of calories sitting unused as fat in my body (only a tad overweight right now).
But if I were to eat 1500 calories a day and on average burn 2500 calories a day, at some point I would have run out of reserve to burn and at that point wouldn't it be better to match match my intake and expenditure instead of further restrictions
I can see it work as part of a healthy diet, but I cant see it work as a complete lifestyle - unless I am missing something about it. Does my BMR reduce to compensate (slower metabolism, longer life?) This in turn would mean that should I resume eating 'normally' again, the weight gain would be much easier.
I'm sure there would have been experiments done (on mice or other animals) with this - a whole life of eating less calories than you expend. Would like to check it out