Bigger portions make people overeat, that’s already well established.
Portions can grow in two ways, however: A portion can grow in size, or by increasing the number of units in the serving.
So here’s a question for you: What would induce more eating, a super-sized sandwich, or 3 normal sized sandwiches that weigh the same as that super sized one? A mega 8-ounce chocolate bar or a package of the same weight with 8 pieces of 1-ounce chocolate treats? In other words, does increasing the volume of the food have the same effect as increasing the number of units?
To answer this question researchers from Belgium and Australia, led by Jolien Vandenbroele, conducted a series of experiments. Their findings appear in a new paper in the journal Appetite.
What’s just enough
In the first experiment 186 participants watched a video during which they could snack on chocolate brownies. The brownies were presented in different sizes: (8, 16 and 32 grams), and different numbers of pieces (1, 2, 3 and 8 pieces). That enabled 12 different brownie plates, in which the total weight of brownies served varied from 8 grams all the way to 256 grams. The different plate presentations also play with brownie size vs. number: people who got 64 grams of brownies (about 2 ounces), for instance, could be presented with 8 small pieces, 4 medium pieces, or 2 large pieces. The participants were unaware that their consumption was being monitored.
And the result: When presented with more food people ate more overall, but the way the treat was presented mattered too.
For the example of the 64 grams of brownies above, when these were comprised of 8 pieces, only 18 percent of people ate the full portion, while 40 percent consumed the entire plate when the brownies were presented as 4 medium pieces, and 60 percent ate the full 64 grams when the brownies were cut into 2 large pieces; the larger the size of the brownie, the more of it the volunteers ate.
So, the bigger the portion the more people eat, but larger slices rather than a greater number of smaller ones produced more overeating.
The second study, involving 193 participants, tested the perception of amounts as it relates to food’s piece size and the number of pieces. People were shown photos of chocolate in 4 different sizes (12.5g, 25g, 37.5g, 50g) and four different unit-numbers (1, 2, 3, 4 pieces), so that the photo could depict total portions from 12.5 grams to 200 grams.
In this study, portions made up of more units…