What does size “small” mean anymore? When it comes to packaged foods, not much. At McDonald’s and KFC, for instance, a small soda holds 16 oz. At Wendy’s, meanwhile, order a small drink, and you’ll get 20 oz. This discrepancy in portion size — along with the fact that standard portion sizes, as defined the government, are so wildly inconsistent with what Americans typically eat — is contributing to a lot of consumer confusion, according to a new study in the Journal of Consumer Research. And that confusion may be driving our tendency to overeat and become obese.
The two authors, Nilufer Aydinoglu at Koc University in Istanbul and Aradhna Krishna at University of Michigan, contend that food size labeling has a significant impact not only on how much food people think a package holds, but also on their actual consumption as well as their perception of how much they ate. That is, when a large size package of food is labeled as “small,” people will think it contains less food, and they’ll eat more of it unknowingly. (More on Time.com: Figuring Out Food Labels)
To test that theory, the researchers conducted a series of experiments. One of them involved two packages of nuts, one clearly containing more nuts than the other. To some participants, the packages were presented as “small” and “medium” in accordance with their actual contents; to others, the labels were reversed, and the larger portion was labeled small. As the researchers predicted, the mislabeling caused people to underestimate how many ounces of nuts were contained in the medium-sized bag when it was labeled small; it also led people to underestimate how much they ate out of those bags, even while they ate more nuts from “small” bags than from “medium” sized ones. (More on Time.com: Top 10 Most Dangerous Foods)
Interestingly, the size effect didn’t work in the other direction: when small bags were labeled “medium,” it didn’t cause people to overestimate actual size or consumption. That may have something to do with people’s wishful thinking when it comes to food, the authors write:
… two conﬂicting goals are salient for consumers when making food consumption decisions: the hedonic goal of taste enjoyment (and possibly the urge to eat more) versus the more utilitarian goal of maintaining good health (and psychosocial motives of body image and self-presentation). In an effort to reconcile these conﬂicting goals, consumers may be inclined to respond to incoming information selectively to minimize guilt while satisfying their hedonic urges. Accordingly, they may be automatically more willing to believe a label that professes an item to be smaller (vs. larger) in the range one can associate with that item. Thus, a small size item mislabeled as “large” (or “medium”) is less likely to be believed by consumers than a large size item mislabeled as “small” (or “medium”).
In other words, we’re eating with our eyes closed. It’s no secret that portion sizes have increased astronomically in the past few decades — the average bottle of Coca-Cola held 6.5 oz. in the early 1960s, but the bottle you buy at the store these days is about 20 oz. (a size that contains 65 g of sugar, by the way) — yet even though the bigness of our food is plainly visible, we tend to see only what we really want to see. Or, rather, what the manufacturer wants us to see. And it’s not just food manufacturers; clothing makers also like to downsize their products through labeling — marking a true size 12 down to a 10, for instance — because it makes people feel thinner and more likely to buy. (More on Time.com: Video: Huge Fast Food)
“An implication of our results is that consumers can continue to eat large sizes that are labeled as smaller and feel that they have not consumed too much,” the study’s authors said in a statement. “This can result in unintended and uninformed over-consumption, which is clearly ridden with significant health ramifications, and size labels could be contributing to the rampant obesity problems in the United States.”
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