Neither bribing or punishing is a good idea. Why don't you just put the food in front of her and ignore her. When she finally realizes she won't get any attention she will eat. (She may go hungry for a couple of days, but that won't kill her.) Children never starve to death when there is food in the house.
We never encouraged our children to eat. We put bowls of food on the table and I gave them each a small portion of everything. When they wanted more I let them choose what they liked best. Maybe one child was ravenous one day and not particularly hungry the next. That was OK with me. We only served wholesome home-cooked food.
It's not a good idea to start force-feeding her, or "making" her eat. No child will starve themselves to death if food is available, so when she's hungry enough, she WILL eat. It's become a battle of wills and a way of getting attention (albeit negative) for her, so you need to stop it before it gets any worse. Simply explain that she's a big girl now and she needs to eat properly. She'll have the option of breakfast, placed calmly before her, and if she doesn't eat it tell her that she will then have to go hungry until lunch. Take it away if she hasn't touched it in half an hour, and don't focus everything on that mealtime; talk about your plans for the day or something, not the food. Give her lunch, and the same rules apply. She'll very likely cry and scream and try to get the attention back that she was getting before, but don't give in, it doesn't last long! Don't offer her snacks either, other than something really healthy, you don't want to "reward" the refusal to eat real meals. They catch on pretty fast that you mean business when their stomachs are rumbling. Once she eats on her own, praise her, and set up a chart where she puts stickers on for every meal eaten; it doesn't have to be a full meal, kids that age go through phases where they stop growing so much and their appetite diminishes, it usually comes back with a vengeance soon enough! There's loads of child-friendly vitamin/mineral supplements that you can give her if you're really worried about that side of it. I know it seems to take over your life right now but you'll (hopefully!) look back in 6months and marvel at the difference... Hope that helps :o)
You may have to check with the doctor to see if she is getting enough and maybe to rule out something being wrong. Sometiimes kids can't tell us that they don't eat because of that. My son wouldn't eat when he was younger either, and the doctors told me that when he was hungry to make sure he got good food to eat. I also used ensure and added a little ice cream to it and said it was a milkshake at times to make sure he was getting enough vitamins and minerals. Talk with your doctor, i'm sure they have many more suggestions.