January 31/Pittsburgh/PRNewswire -- Portion sizes have steadily increased over the last few decades, with consumers demanding more food and larger beverages from companies happy to accommodate and capture the market share. However, new research from Carnegie Mellon University suggests that not only do larger portions lead consumers to enjoy the foods they eat less, they also reduce how often people consume those foods. 

Each bite of a food or sip of a drink is enjoyed less than the previous one, a familiar phenomenon called "sensory-specific satiety." A well-known fact is that the more someone eats or drinks, the more satiety reduces the enjoyment of that food or beverage. So consuming a larger portion means a reduction in the average enjoyment of the food or drink consumed.

The degree of satisfaction at the end of a meal also influences how long someone wants to wait to eat a food again in the future, as revealed by research conducted by Carey Morewedge, associate professor of marketing at Carnegie Mellon's Tepper School of Business, and his colleagues. Research participants who ate chocolate truffles were given a coupon for a free bag of truffles, which they could pick up anytime in the subsequent two weeks.  Although all participants redeemed their coupon in the following two weeks, the more participants reported feeling fully satisfied after they finished their last truffle was the key predictor of how long they took to pick up their free bag. Critically, participants who ate a larger portion of truffles, who were most satisfied after eating, took a full four days longer to redeem their bag of truffles than did participants who only ate one truffle.    

"Our conclusions suggest that how much we enjoy our last bite of a food -- the end of an eating experience -- appears to determine how long we will choose to wait before eating the same food again," Morewedge said.

"Although people often say they prefer larger portion sizes, especially for foods that they really like, our research indicates that consumption of larger portions can ultimately decrease the frequency at which these foods are consumed. This suggests people and companies may actually be better off with smaller portions. People will enjoy the food they eat more, and eat the foods they enjoy more often. Companies will benefit from more frequent repeat purchases."

Another interesting finding of the study was that distraction while eating, like watching TV, can cloud the association that people develop as to their enjoyment with food, thus, altering their end-of-consumption liking for the food. In one of the experiments, participants who were distracted while eating were not influenced as much by their enjoyment of the food to consume that food again, as participants who were not distracted.