I wanted to find some scientific articles to back this up, but it seems to be that everyone claims they have no idea why "morning" sickness happens at all. However, this worked for a me and a number of other mommy coworkers. It's totally counterintuitive, but making sure your tummy doesn't totally empty out seems to keep that unpleasant feeling at bay. I should temper this with the fact that while I had 24 hour queasiness, I never was one of those women who actually puked during the first trimester. The funny thing is I grew sort of attached to the unpleasant feeling, because it was my indicator that I was still pregnant. There's this phase around the beginning of the second trimester when the fatigue and nausea disappear, but you're not really showing yet or feeling the fetus move that had me totally neurotic. At the moment I'm in the honeymoon stage, with lots of fetal movement, but no real downsides to being pregnant.