Portion sizes

The unexpected result of food in smaller portion sizes

One common suggestion to slow down the inexorable increase in human plumpness is to make sure we are offered snack foods in small packets. No doubt it stops some people overeating. For me, if I want chocolate, my taste buds demand 50g and is not satisfied by something prettily packed in 20g units. All the same, will creating snacks in small packets reduce the amount people eat?

The 100 Calorie packet
The 100 Calorie packet (420 kJ) has become popular internationally and has crept onto the Australian market. To see the response to food in smaller packs, researchers from the University of Kentucky and Arizona State University gave either small or large packets of M&Ms to people who were classified as either “restrained” or “unrestrained” eaters. In simple language, a restrained eater is one who is likely to have followed weight loss diets and be watchful, and probably concerned, about what and how much they eat in order to control their weight. In contrast, unrestrained eaters generally don’t get too fussed about kilojoules or fat content (this is not to suggest they eat poorly or overeat; food is just not a source of emotional concern).

The subjects were given four packets of either regular M&Ms or mini-M&Ms with 50 Cals (210 kJs) each or one packet with 200 Cals (840 kJ). When the snack was presented in small packets, people presumed that they were getting a ‘calorie controlled’ food, especially with the mini-M&Ms, yet also estimated the 4-pack of M&Ms Calorie content to be much higher than regular M&Ms in the single large packet (285 Cals v 205 Cals; 1200 kJ v 860 kJ).

Then it gets interesting
So, are you with me? Basically, the consumers thought that small foods in small packets were higher in kJs, but being in small packets meant that they were also seen as "calorie controlled" portions by the consumer. What I found interesting is that, not being aware that their snacking was being monitored, the restrained eaters ate 20% more M&Ms when they were in small packets than when they were given the large packet!

The researchers reckon that restrained eaters freak out when their brain sees something that is saying “We are small in size, and we are in a small diet packet because that means we are calorific and taste yummy”. The small packet makes the restrained eater stressful knowing that, on one hand the packet is small, yet on the other hand, the snack is high kilojoule, weight for weight. The attendant stress leads to uncontrolled eating and a greater consumption of the snack.

Naturally, the unrestrained eater is more likely to rely on internal appetite cues to tell them when enough is enough, so being given small packets meant they ate less than restrained eaters. However, it is not as simple as all that because unrestrained eaters ate more, comparatively, when given the large packet. Maybe they will benefit more from the smaller packs on the market.

What does it all mean?
Frankly, I don’t know. Why I tell you about the study is because it alerts us to the less tangible fact that how much we eat under different circumstances relates more to our relationship with food rather the food itself. The constant blabbering about being overweight, snack food fears, follow our latest diet, worry about the size of your bum style dialogue can only be creating more and more restrained eaters and that is just plain not healthy. The portion-controlled snack food may not help the restrained eater to control their eating at all and may, inadvertently, cause more stress than they need.

Reference: Journal of Consumer Research 2008; 35 (October): 391-405