In recent years countless food manufacturers have been "sub-packaging" their foods into smaller portions in an apparent effort to curb folks from overindulging. You can usually find 100 kcal multi-packs of chips, pretzels, chocolates and all sorts of junk foods. Despite the very obvious negative environmental impact of all this excess packaging, what, if any, impact does such packaging have on people's consumption.
Thankfully, Wansink and colleagues had previously published a paper in the journal Obesity investigating this very question.
I previously discussed another study by Wansink that essentially showed that when snacks are served in bigger bowls, people tend to eat more of their contents.
Thus, it would seem reasonable to think the reverse was also true in terms of small packages for snacks, as in the case with these hyper-packaged 100kcal bags of junk.
So the same authors sought to address this issue, and also to check if the effect on consumption of small packages differed between overweight and normal weight individuals.
A total of 42 undergraduate students participated in the simple study which basically had the participants snack on crackers while watching a sitcom -- now THAT is what I call research!
Half of the participants were given one large 400-calorie package of crackers or a similar-sized package that had then been sub-divided into four smaller 100-calorie sub-packaged crackers. They were blinded to the purpose of the study.
After watching the show, the crackers not consumed by the participants were counted to calculate everyone's caloric intake. Also, each participant was asked how many crackers they think they consumed.
Turns out, overweight participants ate significantly more crackers when eating from one large package than from four small packages. In fact, they consumed more than double the number of calories with the bigger package: 384 calories versus 176 calories.
Surprisingly, there was no difference in consumption between package conditions among the normal-weight participants.
Despite this difference in consumption, what is odd is that all groups (small package and big package, overweight and normal weight) underestimated how many crackers they had eaten by more than 60 per cent!
This suggests that the smaller packaging doesn't make people more accurate at keeping track of what they ate.
So why the difference between overweight and normal weight participants? The authors suggest that: "Obese people were more likely to rely on external cues to stop eating, [and thus] the perception of package count might play a crucial role for overweight participants in determining their food intake."
This article first appeared on PLoS Blogs and republished here under Creative Common licence.