SOUP, ANYONE?

Want to tame your appetite? At least in the short run, it might help to start your meal with soup of some other food with low calorie density, say researchers at the Pennsylvania State University in University Park. (A food's calorie density is its calories divided by its weight.)

Barbara Rolls and co-workers fed 24 lean women one of three "preloads'--each with 270 calories--five minutes before lunch: (1) a chicken-rice casserole, (2) me same casserole served with a 12-ounce glass of water, or (3) the same casserole and the same glass of water, but mixed together, heated, and served as chicken-rice soup.

The results: After the soup, the women ate an average of 290 calories at lunch. But after the casserole, they averaged 390 calories at lunch, whether of not they had the glass of water with their casserole.

"We'll try to figure out why in subsequent studies,' says Rolls. Among the possibilities: People may have been less hungry after the soup because it looked like more food. "The casserole looked small, but the soup looked like a lot of soup," she explains. "And there was more sensory stimulation with the soup because it was a big volume."

It's also possible that the water may not have registered on the sensors that assess how hungry we are. "When you drink water on the side," says Rolls, "it's processed by thirst mechanisms, while soup is processed by hunger mechanisms."

Amer. J. C/in. Nutr. 70: 448, 1999.