Welcome to our Forum, rayray.
I'm a little curious about why you starved your Sim, but didn't let him die. Death is the only outcome if you go so long without feeding your Sim. I don't know if Lisa's suggestion will help you because making Ambrosia required very high levels of the cooking, gardening, and fishing skills. If your Sim wasn't allowed to eat, I'm guessing he wasn't a master chef.