Narrator: This is Science Today. For people living in a society that induces chronic stress, it's not uncommon to turn to high-fat comfort foods and put on abdominal weight. University of California, San Francisco physiology professor, Mary Dallman, says from the standpoint of evolution, modest weight gain when you're chronically stressed can be helpful.
Dallman: It's smart as can be because in a chronic stress situation-for instance, a drought or a famine- it's a very neat pool of fat because it sits very close to liver, and when it's mobilized, its energy can be used by the liver to make more glucose.
Narrator: But as Dallman notes, there's not much worry about famine in today's fast-food culture.
Dallman: Convenience food is all over the place-every block you walk to has the availability and low price of food that is really high fat or high carbohydrate and this can become habitual and that's what is a big problem.
Narrator: For Science Today, I'm Larissa Branin.