My gf has all day morning sickness and had started keeping a food diary. When we looked back at it, she was having a lot of high GI foods, so she found that not long after she was hungry again and then she felt sick. She has started to try eating more low GI foods and more foods with protein in it. Another little trick is that she sips natural mineral water or soda water when having meals, so she keeps burping (sorry if TMI) and pushes her food down IYKWIM.