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Mindless Eating

Posted by tinako on July 15, 2010

Brian Wansink

I listened to a very interesting 2008 Yale Rudd Center interview of Brian Wansink, professor at Cornell Universty, director of the food and brand lab there, author of the book Mindless Eating, and appointed by the White House to be the executive director of the USDA center for nutrition policy and promotion.  Here’s a rundown:

The basic theme is that the food environment has a remarkable impact on the way we eat.  Wansink discussed common myths, the first one being that we make good decision about when to stop eating.  He asked 150 French people how they know when they are done eating and they would answer, “When I’m no longer hungry.”  150 Chicagoans had different answers, such as, “when my plate is empty,” or “when everyone else is done eating,” or “when the TV show I’m watching is over.”  These are external cues.  The problem is that our life is filled with cues that all tell us to eat more, whether it’s the size of our plate, etc.  He thought the reason for this cultural difference was routine and personal environment.  Any culture where there’s a very routinized way to eat, such as in the U.S. having oatmeal for breakfast every day, will have one less meal for things to go awry.  I think his point here was that even though some Americans do have some routines, other cultures have more.  By personal environment he means that in Europe there are not so many big box grocery stores, it’s difficult to bring home many groceries at once (on the bus/subway, small car, or walking), and refrigerators and cupboard space is small, so there is a natural limitation for how much food you will have on hand.

Most people believe they know when they’re full, but Wansink’s research shows we eat with our eyes.  They set up trick soup bowls that would refill without the subject knowing.  The subject would keep eating the soup and be stopped by the researchers after 15 minutes.  Out of 160 cases, only two people figured out something was going on.  The typical person eats 73% more soup than the control subject with a normal soup bowl, some of them eating a quart of soup, and they report not feeling full.  They get the same results in France and Taiwan, but they have trouble doing the experiment with breakfasts and lunches because those cultures have fixed ideas about those meals.

In another study they offered subjects chicken wings, and then either cleared the bones away right away, or let them pile up.  Those whose bones were cleared away would eat 50% more, a difference of 250 calories.  To add to this, on their way out they were all offered a 400 calorie cookie.  Of those who had seen the bones pile up, only 25% took the cookie.  In the other group who had no visual cues of how much they were eating, almost everybody took the cookie.

They did research which showed that people would serve themselves 22-28% more if they had a larger plate.  They wondered whether this effect could be educated out of people, so they took graduate students and spent 90 minutes explaining this concept to them, with demonstrations and videos.  Six weeks later the students were invited back for what they believed was an unrelated study; those with larger plates still ended up serving and eating 53% more.  Researchers then asked the students whether they had served themselves more due to the size of the plate and they said no.

That’s why these cues have so much power over us – because even when we’re aware of them, we’re unwilling to acknowledge that we could be fooled by them.  That’s the biggest myth – that we can learn to overcome these biases.  Education is not the solution.

The shape of a glass is another fooler – short squat glasses appear to hold less than equal-volume taller glasses.  This is because we judge the volume by the height of the liquid – we under-account for the width.  Even experienced bartenders can be fooled, even when they have been told about the effect.

They looked at how package size affects serving size.  They gave couples packages of ingredients for a spaghetti dinner.  Half of the couples got 2 lbs. of meat, 1 lb. of spaghetti, and half a gallon of sauce, and the other couples got double that.  The second group of couples made and ate about 30% more.  The package size cued the mind about the appropriate amount to eat.

They found that people will eat 92% of what they serve themselves, which is another hole in the idea that we stop eating when we’re full.

They did a study looking at how recipes have changed over time in The Joy of Cooking, to see how calories in home cooking have changed over the years, eight editions running since 1937.  They looked at calories and serving sizes of recipes where the names haven’t changed.  They found that every recipe but one increased in the calories per serving.  On average they increased 63% per serving.  A 1937 serving of beef stew might be 100 calories and would be 163 calories today.  About 2/3 of that increase was due to a change in the recipe, adding fat, sugar, nuts, more meat, etc., but 1/3 of the effect was just from dividing the recipe into fewer servings.

They did several studies showing that people will decide they do or do not like a food or drink based on external cues such as a descriptive name, package label or a good review, not the food itself.  Our perception of taste is tremendously biased.

They found that we make between 200 and 300 eating decisions per day (examples: what cereal to have, how much, how much milk, sugar? a second bowl?, it’s a half hour to lunch – should I have a snack?).  This is too many to make conscious smart decisions – as a matter of practicality, we make so many mindlessly.  We’re too busy to try to remind ourselves of all these tricks.  If our personal environment is set up against us, it’s almost impossible to fight against it through willpower.  The answer to mindless eating is not mindful eating, it’s to rearrange our environment so that we can eat mindlessly without overeating.

For two examples, if a large plate causes you to eat too much, get smaller plates.  Or, their studies show that where products are in your cupboards has a remarkable effect on how often you choose them – so rearrange your cupboards with healthier items at eye level.

How do you get manufacturers to help with this?  They did studies that show that the larger the package size, the more you eat.  As you might expect, they also found the opposite to be true as well – 70% of people ate less of smaller mini packages.  Yes, in 1996 Professor Wansink invented those 100 calorie packs and pitched them to the snack companies.  At first the manufacturers didn’t believe they could sell less food for more money.  About a year and a half later Nabisco came back to him and he verified that his research showed that at least half of customers would pay up to 20% more for an item that would help them eat less.  A few years later Nabisco put out the product.

He talks about some work they’re looking at in schools, changing lunch rooms around to promote fruit consumption.  He is also (in 2008) doing a compensation study to find out if the time of day when kids eat lunch affects the quality of the lunch they choose.  Later lunches do tend to be much less healthy, but for the rest of the day, girls tend to compensate by not eating so much, but boys do not.

The Small Plate Movement: Changing plate size from 12.5″ to 10-10.5″, people serve themselves about 22% less without even realizing it.  They feel full.  Below 10″ people will go back for seconds or thirds, erasing the effect.  So they’re starting this Small Plate Movement targeting consumers, restaurants, and plate manufacturers.  They ask consumers to take the small plate challenge for one month, use a smaller plate and see what it does.  The typical person in their pilot study lost 2 pounds in the first month or two, without trying, but in the third month they see an uptick in weight loss because the person feels empowered and adds in some more efforts.  They’re also targeting restaurants because it’s win-win.  Restaurants can serve less and customers will feel they’ve eaten more and be more satisfied and healthier.  This could work for glasses as well, switching to taller, thinner glasses.  However, this all takes time to implement due to investment in plates and glasses.

You can also visit the Cornell website Mindless Eating.  This looked really interesting, so give it a click.


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