Why do women have to drink so much? I have a new girlfriend who is very loving and sincere but come dinner time she is a drunk. ?

Of all my girl friends I can honestly say most of them don’t drink, or drink in excess. Considering this is a new girlfriend, you may need to run while you can. 

If this is serious, talk to her about your concerns. 

I'd say she has some serious emotional issues. You might try to get her in to someone to sort it all out. I can't imagine being drunk all the time, I'd spend to much of my life hung over, which is no fun.

Make her your ex GF. You do not need a drunk in your life. It will get worse.

Not all girls are like that so it's time to find a new girlfriend.

You don't have a new girlfriend. You don't even have an old girlfriend. You've clearly never had a girlfriend. You make that obvious with your question. 

Not all of us do that. It also sounds like you didn't really get to know her before you started dating her and we don't know why she drinks as much as she does.