Big Plate Big Meal (Big Butt)

We’ve all heard the statistics about how often we think of sex, but what about food?

Studies have shown that we face an average of 226 food-related choices in a day, but we are only conscious of our decision making in about 15 of them. That’s more than 200 mindless decisions of the what-when-where-how much-who with of food occurring each day. It’s helping yourself to seconds because the bowl is right there; taking a gulp of orange juice because you saw the carton when you opened the refrigerator; or a doughnut because someone brought a box into the office. Scientists refer to these as environmental cues, and when we aren’t mindful, they rule our food choices.

Size matters.

Portion size is one the the most ubiquitous and dangerous of the environmental cues. Here’s what happens when it’s not our eyes, but our servings that are bigger than our stomachs.

Mindless eating can lead us to judge fullness by how much is left on the plate instead of what our bodies tell us. The classic study in this area of  inquiry is the bottomless bowl experiment, which won its author the 2007 Ignoble Award for improbable research. Test subjects sat down to identical-looking bowls of Campbell’s tomato soup, and they were instructed to eat as much as they wanted. One group got normal bowls of soup. The other group got bowls that were secretly and invisibly self-replenishing. The subjects given the bottomless bowl ate two-thirds more soup than the group with the normal bowl.

We pour larger drinks into short, wide glasses. Given taller and shorter cocktail glasses of equal capacities, 30% more alcohol is poured into the short glasses., even though most people will guess that the taller glass holds more liquid. Even bartenders are prone to this bias typically pouring 20%  larger shots into short, wide glasses than into tall, slim ones.

When we aren’t eating mindfully, we’re susceptible to unit bias?we’ll eat a serving size that has been defined for us, rather than considering how much we want. One test of this involved a  bowl of M&M’s in the lobby of an apartment building. Some days the researchers left a tablespoon-sized scoop, and other days they left a scoop that was four times larger. On average, people helped themselves to 1.67 times more candy when the big scoop was used. The results stayed the same when they followed up with studies of pretzels and Tootsie Rolls.

At the dinner table, when eating is a more deliberate act than a handful of pretzels, we still calibrate our consumption to portion size rather than appetite. We tend to eat almost a third more food when portions are large, usually without even noticing. Followup studies with over-eating test subjects suggest that we don’t even want to know: after a super-sized meal, most people believed that they had eaten their usual amount, and even when shown contradictory proof, 69% of them insisted that they had just been extra hungry. Only 4% would fess up to being influenced by the portion put in front of them.

Fifty years ago, the standard dinner plate had a 9 inch diameter.

Today, it’s most likely to be 12 inches. We know that restaurant portions have ballooned in recent years, but even at home we are serving up larger portions. It may be impossible to avoid the environmental cues that encourage us to eat, but recognizing them is a step in the right direction.

Read the full abstract of the bottomless soup bowl and other studies of the mindless eating phenomenon at the Cornell University Food and Brand Lab. Cornell Professor Brian Wansink has conducted more than 250 experiments proving that people have no idea how much they’re putting in their mouths or why.

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