If somebody gives us a huge bowl of candy, we are likely to eat more of it than if someone gives us a smaller bowl of candy.
Scientists have studied the so-called portion size effect in some depth.
One review of the research found that when a portion size is doubled, people consume an average of 35 percent more.
Food outlets often advertise larger portion sizes to attract customers, and many health professionals believe that this tactic might play a role in the rise of obesity in the United States.
For this reason, health-conscious people around the world make sure to only give themselves small portions of foods that some may call unhealthful.
Despite a great deal of research into the negative consequences of portion size, very few studies have focused on the potential benefits. Could increasing portion size of healthful snacks increase their consumption?
With this in mind, researchers from Deakin University in Australia recently set out to see whether the effect would work in reverse.
The study, which Prof. Chris Dubelaar led, was a coordinated effort between scientists in Australia and France. Their findings now appear in the journal Food Quality and Preference.
Portion size revisited
In order to investigate, the team designed two complementary experiments. The first involved 153 university students in a laboratory setting. The scientists gave them large or small portions of healthful apple chips or unhealthful potato chips.
As expected, the participants to whom the team gave the larger portions of snacks — even the healthful versions — ate significantly more than the group with the smaller portions.
The second phase took place at a film festival. In total, the researchers gave 77 participants a small or a large bag of baby carrots. They watched either a film about a restaurant, which included many scenes involving food, or a romantic comedy with no particular food references.
Again, those with the larger bag ate more of the healthful snack. Interestingly, the effect was less pronounced in the group that watched the film about the restaurant; this demonstrates the significant impact that the environment can have on our eating behavior.
Prof. Dubelaar thinks that this could provide an “opportunity for those seeking to control intake to consider their environment when they’re eating to help reduce the effects of portion size.”
Overall, the study’s results give an interesting insight into the convoluted world of food psychology. They might also offer some new ways to improve our eating habits.
He continues, “For example, parents trying to get their children to eat more veggies could serve up larger portions. This would also work for healthy snacks such as fruit or any food you want someone to eat more of.”
The authors suggest that beginning a meal with a large portion of healthful food before a smaller plate of unhealthful food might be a useful approach.
Because obesity is a growing concern in the U.S. and elsewhere, understanding the nuances of our relationship with food is more important than ever. Though this study used a relatively low number of participants, it offers fresh insight and is likely to spur future investigations in a similar vein.
There is a myriad of variables that scientists could analyze in follow-up work. For instance, healthful and unhealthful snacks often have very different flavor and texture profiles, so understanding how each of these subtle differences impacts the portion size effect will be interesting.
Until more studies are carried out, the take-home message is: Don’t worry how large the portion is, worry about what you are apportioning.