Between the opening nights of All About Eve and Mean Girls, an average moviegoer’s portion of popcorn increased sevenfold. Starbucks' gut-busting Trenta is more than double the size of its original tall paper cup. The surface area of an average dinner plate is as much as 36 percent larger than it was in 1960. Even some recipes in the most recent edition of The Joy of Cooking, the staple of middle-class kitchens everywhere, expanded 42 percent from their 1931 versions.
And as food portions have increased in size, so have Americans. The connection might seem obvious. But new research into the psychology of eating suggests that in some cases, more can actually mean less.
For one forthcoming study in the Journal of Consumer Research, researchers from the University of Utah invited 60 undergrads to sit down at a popular Italian restaurant and order a meal. Over two days—two lunches and two dinners—the grub arrived with some custom cutlery. Researchers swapped in forks that were either 20 percent smaller or 20 percent larger than your standard utensil. After weighing each dish before and after the meal, they found that students wielding the bigger forks ate less than those eating off the smaller ones.
Why would petite utensils convince some kids in Utah to bite off more than they can chew? Here's one theory: When eating with a small fork, each forkful hardly makes a dent in the dish. But with bigger forks, each bite marks measurable progress in the consumption of the meal. If the researchers are right, fork size could be the quickest dietary fix since chewing. "[I]f we are not chewing longer," they write, "then consuming from a larger fork may actually be more helpful in controlling overconsumption."
When it comes to evaluating how much food to eat, we're more likely to rely on our eyes than our stomachs. As Cornell professor Brian Wansink writes in Mindless Eating, visual cues (a half-glass of juice or a full bowl of soup) have a greater effect on our eating habits than the physiological feeling of fullness. That's why the drink served in a short, wide glass seems less filling than the drink poured into a tall, slender one, even when the two glasses contain the same amount of liquid. As we drink up, we're evaluating the glass’s perceived contents, not the sensation of liquid sloshing around in our stomachs.
Size matters, but so does heft. In another forthcoming study in Food Quality and Preference, neuroscience researcher Charles Spence and his colleagues asked 50 volunteers to hold bowls of Greek yogurt, then eat it. The volunteers rated their perceptions of the yogurt’s ﬂavor, density, and price. Spence found that those holding heavier bowls considered the yogurt “weightier”—both denser and more expensive—than those holding lighter bowls. Spence writes:
Interestingly, both of the attributes that were most affected by weight (perceived density and price) are related in society with weight properties: people commonly describe very dense foods as being “ﬁlling” or “heavy” and heavy perfume bottles as being expensive and/or of higher quality.
So eating out of a Styrofoam container with a plastic fork could make a chicken dinner feel lighter, while eating fast food fries from a weighty bowl could make the fries seem heavier—and classier, too.
These subtle nudges away from supersized portions may be a lot easier to stomach than consciously down-shifting our diets. Just a few tweaks in the tableware—serving up smaller, heavier, plates and larger forks—could help us eat better without even thinking about it. And really, who has time to think and eat?
Look out for Watch Your Mouth, GOOD's food column, every Monday.