“Presenting children with a wide variety of different snack food products may make it difficult to predict their fullness. Our study suggests that if parents choose to give snack foods to their children, they may wise to stick to the same products,” said Dr Charlotte Hardman, one of the authors of the study, which has been accepted for publication in the American Journal of Clinical Nutrition.
She continued: “We know from previous work with adults that we have beliefs and expectations about how filling foods will be, and these expectations can change. Moreover, fullness expectations are important determinants of meal-size selection, for example, foods that are believed to be more filing are selected in smaller portions.”
To explore this idea in children, 70 11-12 year-olds completed measures of expected satiation, perceived volume, familiarity and liking across six energy-dense foods: a chocolate bar, a processed cheese product, chicken nuggets, cheese dip with a corn and potato snack, a jam donut and a lemon cake slice.
Participants were shown an image of one of the foods, along with an image of a comparison food (pasta and tomato sauce). They were instructed to change the size of the comparison food until they thought both foods would be equally filling. This generated a PSE (point of subjective equality) - the point at which the amount of pasta and sauce was expected to be equally filling. Dividing this PSE by the actual energy content of the food yielded an ‘expected satiation’ ratio.
To determine familiarity (defined as the participant’s current frequency of consumption), the children were asked how often they ate each food. For each participant, a familiarity score was obtained by averaging familiarity ratings across the six foods.
To investigate their primary hypothesis - that familiarity promotes higher expected satiation - the researchers calculated the correlation between expected-satiation scores and familiarity scores.
The researchers found that familiarity helps children predict the fullness that is associated with snack foods. The team also discovered that children who were infrequent consumers tended to rely on the physical appearance of the food, for example volume, in their judgments about fullness – a strategy that would be expected to promote selection of larger portion sizes.
“The effect of familiarity was considerable,” said Hardman. “We estimate that children who were highly familiar with the snack foods expected them to deliver twice as much satiation as did children who knew the foods but who never or rarely consumed them.
“In adults, expected satiation is highly correlated with self-selected portion sizes. Therefore, familiarity may play an important role in determining the portions of snack foods that are selected and consumed by children.”
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.3945/ajcn.111.016873 “Children’s familiarity with snack foods changes expectations about fullness.” Authors: Hardman, C.A., McCrickerd, K., and Brunstrom, J.M.