I rarely eat when I go to the movies, but when we went last weekend, my husband was in the mood for some popcorn. We ordered a bag to share—choosing a “medium” size for no other reason than a “small” size sounded, well, small and “large” sounded more like “family size.” So, when we were handed this enormous bag of popcorn—enough for about six people—it got me to thinking. If the folks running the movie theater are deciding what’s a “small” or “medium” or “large” serving of popcorn, do we blindly accept those labels? Do we tell ourselves that “medium” means “moderate?” Do we go ahead and eat half of that “medium” bag of popcorn, even though it’s clearly a large amount of food?
It turns out that in many cases that’s exactly what people do. In a paper published earlier this year in the Journal of Consumer Research1, it was noted that most people have a hard time estimating the volume of a particular food simply by looking at it—or even how full they are after eating it. So, it’s a lot easier to rely on someone else’s judgment. In this case it’s the size of a medium bag of popcorn to tell them what’s an appropriate amount to eat. This “size label effect” can lead to what the authors called “guiltless gluttony,” where we mindlessly eat large amounts of food, because the label has us believing that we’re eating a lot less than we really are.
This is a real problem, though. When it comes to eating, many of us have an internal tug-of-war going on. We want to believe we’re eating less, because that shows that we care about our health and our weight. But at he same time, we also want to eat a lot—for the simple reason that eating is fun and pleasurable. That’s why this crafty labeling helps us resolve this conflict.
Interestingly, there aren’t any standards for what’s labeled “small” or “medium” or “large.” It’s entirely up to the vendor. What was originally the “regular” size fries at one fast food chain is now the “kids” size, and what used to be the “supersize” portion is now a “large.” Drink sizes also can vary a lot from place to place—and from beverage to beverage. Depending on where you get your coffee, a “small” could range anywhere from 8-12 ounces and a “large” could be 16 ounces or even 24. A 32-ounce soda is a “large” drink at one fast food chain, but it’s a “medium” at another (where a large is 40 ounces—and another 80 calories).
There’s a similar thing going on with women’s clothing. In the US, clothing sizes aren’t standardized, so we run up against something called “vanity sizing.” Many garments are labeled smaller than they actually are, which leads women to believe their bodies are smaller than they actually are.
So, what’s in a name? Not much, it seems. Portion size matters, of course, but we can’t rely only a size label to actually tell us how big that portion really is. And we’ll never get anywhere as long as we’ve got size labels on foods that have us convinced we’re not overeating—and vanity sizing on clothing that just hammers the point home.
1 Aydingolu NZ and Krishna A. J Consumer Res. 37:1097, 2011.