Eating just one potato chip takes some serious self-control, so researchers from Cornell University’s Food and Brand Lab came up with a novel way to keep snackers from overindulging: inserting edible “stop signs” in stacks of packaged chips.
Researchers conducted two studies on a total of 98 undergraduate students: in both, students were given tubes of Lays Stackables potato chips to nosh on while watching video clips in class. In the first study researchers inserted red-dyed chips at regular intervals in the stack — either at the seven-chip mark (one serving size) or every 14 chips (two serving sizes). A control group got a regular, unmarked stack of chips. In the second study, the red chips were inserted every five or 10 chips.
None of the participants were told what the red chips were for, but in both studies, students who got the tubes with the subconscious stop signs ate less — about 50% less than those in the control groups.
In the first study with the seven- and 14-chip indicators, students ate an average of 20 and 24 chips, respectively, compared with 45 chips consumed by the control group. In the second study, those with the five-chip and 10-chip markers ate 14 and 16 chips, respectively, compared with the average 35 chips eaten by the control group.
Students snacking from the chip tubes with stop signs also more accurately estimated how many chips they’d eaten. They were able to guess their total consumption within one chip, while students in the control groups underestimated their eating by about 13 chips.
People generally eat what’s put in front of them if it’s palatable, the authors write. “When you’re eating something small like chips, the process starts to be become automatic and you get into a cycle,” says study researcher Paul Rozin of the University of Pennsylvania.
Such mindless habit-eating helps explain why some people go overboard while snacking. Other reasons, the study notes: people aren’t good at self-monitoring how much they eat, or they eat what they believe — incorrectly — is an appropriate portion.
“By inserting visual markers in a snack-food package, we may be helping them to monitor how much they are eating and interrupt their semi-automated eating habits,” lead researcher Brian Wansink, director of the Cornell Food and Brand Lab and author of Mindless Eating: Why We Eat More Than We Think, said in a statement.
Overall, the researchers say, the edible stop signs reduced snackers’ intake by about 250 calories.
“Generally people tend to eat ‘one’ of something,” says Rozin. “People will eat one piece of fruit, one sandwich. By using markers with food you can indicate: ‘This is one.'” The authors call for further research into what other foods could easily be segmented to help people consume less.
They conclude in the paper:
The effect demonstrated and replicated in these studies stands as perhaps the largest practicable procedure to decrease food intake in the literature … [A] manipulation of the sort we used could lead to a loss of weight of greater than one pound a year, a major part of the American annual weight gains over recent years.
The study was published online by the journal Health Psychology.