Don't "think". Someone like yourself who engages in such activity can hurt himself and others.
To answer your question, ketones are not harmful. In fact they're a great source of energy.
Ketosis is not ketoacidosis.
The suppressed appetite may be a chemical "starvation" response, though I was eating very nice meals. I lost my weight *very* slowly, 25 pounds over a year's time. I was not hungry or frustrated a single moment. Men find it much quicker to lose weight than women on lo-carb.
I highly recommend it. I am convinced that overconsumption of carbs is behind our country's obesity problem.
The real indicator is the increase of type-2 diabetes in children, which was unheard-of twenty or thirty years ago. It even used to be called "adult-onset" diabetes. Now, it's almost an epidemic among children. This can't be blamed on video games or lack of exercise.