When I was pregnant with my first baby, I had horrible morning sickness. The only thing that settled my stomach was Tim's Cascade brand salt and vinegar potato chips. I ate them with every meal, three or four after my cereal or my sandwich or my broiled chicken and roasted broccoli. Without the chips -- and only that one flavor and that one brand worked -- I felt like crap all the time.

Scientists have long wondered what triggered morning sickness, and what its function was in a pregnancy. The theory has always been that morning sickness was a sign of a healthy pregnancy, although not all healthy pregnancies include morning sickness (my second did not) and not all women who suffer from morning sickness have healthy babies.

Now, there is a new theory about why so many of us feel so horrible during those first weeks: our bodies are responding to environmental factors that might threaten the developing fetus. Specifically, researchers found that morning sickness is most often triggered by the sight, smell, or taste of meats and strong-tasting vegetables, which were historically likely to contain foodborne microbes or birth-defect-inducing chemicals, or by alcohol and cigarette smoke, which can be toxic to the fetus. Scientists also theorize that humans may be the only mammals who suffer from morning sickness, probably because we eat a wider range of foods than our animal counterparts, which can put our developing pregnancies at higher risk.

The implications of these findings could be huge, according to Samuel Flaxman, an evolutionary biologist at the University of Colorado at Boulder. "To say that morning sickness is uncomfortable is a real understatement, and a lot of people are looking at ways to deal with it. But if nausea and vomiting truly serve a useful function, then one has to look more carefully at strategies for dealing with these symptoms."

I would recommend some salt and vinegar potato chips, just as a starting place.