What Could Be The Reason For Head Getting Drunk Feeling After Having Food?

I am inquiring for my neighbor. She is 60. She most always feels good when she gets up in the morning but after eating she gets so drunk in the head she can hardly walk and ends up back in bed. She also get sick on her stomach about every other week. What could be causing this. The only medication she takes is a blood pressure and thyroid pill every morning. She just had a blood test and every thing came back normal except elevated cholesterol. What could be causing this problem. She lost her job because of it and has no insurance. She has had this problem for about a year and it just gets worse. Thanks for your consideration of this.