THURSDAY, Dec. 6 (HealthDay News) -- Believing you had a large meal can make you feel less hungry hours after the meal, a finding that could lead to new methods of weight control, researchers say.

Their study included volunteers who were given what appeared to be either a small or large portion of soup for lunch. The researchers, however, manipulated the amount of soup the volunteers actually consumed by using a hidden pump that could refill or empty a soup bowl without the eater noticing.

Immediately after they ate, the volunteers' level of hunger matched the amount of soup they had eaten, not the amount they had seen just before eating. But two to three hours after lunch, those who had seen a larger portion of soup had significantly lower levels of hunger than those who had seen a smaller portion.

Twenty-four hours after eating the soup, more of the volunteers who had seen a larger portion of soup believed that the portion they had consumed would satisfy their hunger, according to the study published Dec. 5 in the journal PLoS One.

The findings show that memory makes an independent contribution to feeling full after a meal, said the researchers, from the University of Bristol in England.

The results could be used to find new ways to reduce people's calorie intake, they concluded in a journal news release.

More information

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about portion sizes.