Flip through your recent memories and find a visual snapshot of a typical dinner at home. Visualize the tablescape – the placement and the types of dishes, silverware, drinking glasses, and serving bowls. Picture where the food was located on table, how it was arranged, and how much variety there was at that meal. If you can, recall where the food was stored before it was prepared and what its packaging looked like.

Maybe you can visualize this; but probably you cannot. After all, the tablescape of a meal seems like a meaningless detail in the daily drama of our lives. Most of us are more concerned about our frustrations at work, our son’s grades, and our undone “to do” list than we are about dinner table details.

And yet the tablescape you were asked to visualize is filled with hidden persuaders. Each of the innocuous looking items you visualized – packages, dishes, glasses, and the variety of foods – can increase how much we eat by well over 20%. They can also be used to decrease how much we eat. Either way – up or down – the impact they have on us will be mindless.

The problem starts with our cupboards and pantry. Americans are often shocked when they check out the typical kitchen in Europe or in Asia. Where is the island in the middle, where are the rows of new cabinets, the pantry, the refrigerator the size of a Subaru? The micro-size of most foreign kitchens and refrigerators would render most American homes almost unsellable.

The danger of our huge American kitchens is that they give us the space to fill with huge American packages. We can buy bigger boxes of pasta, restaurant-size jars of spaghetti sauce, and chunkier packages of ground beef. Some of us even buy an extra refrigerator.

These bigger packages can save us money and save us an extra trip to the supermarket because we ran out of something. They also lead us to make bigger meals, and eat more food.

Imagine that a professor from a local university approaches an organization to which you belong – such as a Parent Teacher Association – and proposes a fundraiser for your organization. He’ll donate $20 to your organization in your name if you come in to the school kitchen one evening and make a spaghetti dinner for you and your spouse. He’ll even provide the food – a medium-size box of spaghetti, and a medium-size jar of spaghetti sauce, and one pound of ground beef.

What you will not know, however, is that half of the people in your organization will receive not the medium size, but a large box of spaghetti, a large jar of spaghetti sauce and two pounds of ground beef. What you also will not know is that after you finish the dinner he will weigh how much spaghetti, pasta, and ground beef you have left, and how much you cooked, but did not eat.

We have done dozens of similar studies with dozens of different foods. With spaghetti, for instance, we found that the people who were given the large package of pasta, sauce, and meat prepared 24% more – 137 extra calories – than those given the medium packages.

Did they eat it all? Yes. We find over and over, if people serve themselves, they tend to eat most – 92% – of what they serve. (2) For almost all breakfast, lunch, and dinner foods, the result is about the same – people eat 20-25% more. (3) For snack foods, it is even worse.

On another occasion we asked 40 adults at a PTA meeting to watch a video tape and provide some feedback about it. As a “thank you,” they are also each given one of two size bags of M&Ms – either a 1/2-pound bag or a 1-pound bag – to enjoy while they watch the tape. In reality, we do not really care what they think about the tape, we only care about how many M&Ms they eat while watching it. After they finished the video, we weighed the remains in their M&M bag.

The results are dramatic. Those who had been given a 1/2-pound bag ate an average of 71 M&Ms, about the number in a normal-size vending machine packages). Those who had been given the 1-pound bag ate an average of 137 M&Ms, almost twice as many – 264 calories more. Sure a person saves some money by buying the big bag, but if he decides to watch a hundred videos in the next year, it will cost him nine pounds more than if he had bought the smaller bag.

The bottom line: We all consume more from big packages, whatever the product. Give someone a large bag of dog food, they pour more. Give them a large bottle of liquid plant food, they pour more. Give them a large shampoo bottle or container of laundry detergent, they pour more. In fact, with the 47 products we have examined, the bigger the package, the more they use. There was only one exception we ever found: Liquid bleach. Most people know that if they use too much, their socks and shirts experience a religious conversion. They become holy.

Why do we automatically eat (or pour) more from big packages? Because big packages (like big portions) suggest a consumption norm – what is appropriate or normal to eat? (4)

As all of our studies suggest, we can eat about 20% more or 20% less without really being aware of it. Because of this, we look for cues and signals that tell us how much to eat. One of these signals is the size of the package. When we bring a big package into our kitchen, we think it is typical, normal, and appropriate to mix and to serve more than if the package were smaller.

Although we will never finish the large box of spaghetti when we make dinner for two, it makes us think its normal to take a few more than we would if it were a ½-pound box. It bumps up our consumption norms and leads us to bump up how much we serve ourselves.

References

(1) Brian Wansink (2006), Mindless Eating: Why We Eat More Than We Think, New York, NY: Bantam Dell.

(2) We find this 92% figure pops up in our studies again and again. A recent one is Brian Wansink and Matthew M. Cheney, “Super Bowls: Serving Bowl Size and Food Consumption,” JAMA – Journal of the American Medical Association (April 2005), 293:14, 1727-1728.

(3) Much of this discussion on package size is based on the paper, Brian Wansink, “Can Package Size Accelerate Usage Volume?” Journal of Marketing (July 1996), 60:3, 1-14.

(4) This idea of consumption norms was first set forth in Brian Wansink, “Environmental Factors that Increase the Food Intake and Consumption Volume of Unknowing Consumers,” Annual Review of Nutrition (2004), 24, 455-479.