your body shuts down and goes into starvation mode instead of losing weight

How long did you endure that? I kind of get the same when I start a weight-loss diet, but it usually only lasts about three days for me (provided I don't do anything drastic such as reducing my calorie intake by more than 25%).

cannibalize irreplaceable neurons

I don't think that's likely to happen. Neuroplasticity has been widely demonstrated even in adults, hasn't it?