What can happen if you starve yourself for a month?

Do you mean you can only drink water or other drinks with minerals,vitamins, and calories? The outcome can only be known by going through it, which I suggest you don’t. If you have enough calories reserved you may have a chance of survival but can be extremely vulnerable to infections, metabolic disorders like ketoacidosid, hyponatremia, vit c deficiency, osteoporosis, hair loss. Hope it helps