Sunday, March 21, 2010

Week 12: Why we eat more than we should

Distribution Source: CornellCast
Content Source: Cornell University/Professor Brian Wansink
Format: Video
Length: 1 hour, 18 minutes, 43 seconds
Link: Mindless Eating

In honor of my alma mater's historic win today over Wisconsin in the NCAA tournament, I decided to choose a video from Cornell's free collection of audio and video lectures. This week is focused on a fascinating talk by Professor Brian Wansink based on the findings chronicled in his book, Mindless eating: Why we eat more than we think. This topic is of recent interest thanks to numerous cues in my life focused on the issue of food, weight and health. Whether it was my girlfriend watching tonight's kick-off episode of Jamie Oliver's "Food Revolution" (a push to make Americans less fat), my co-worker's refusal to eat at 90% of restaurants around the office following a viewing of "Food, Inc.", or witnessing the intensity/insanity of a two-month extreme nutrition program undertaken recently by a good friend, it is clear to me that people care about food. More specifically, people care about how food relates to health (or lack of health).

The bottom line is perhaps unsurprising: we Americans eat with our eyes, not with our (abnormally large) stomachs. We often don't know when we are full, why we are eating, or how much we should be eating. I saw more than a little irony when, over the course of the hour-long lecture, I realized I had eaten a small plate of leftovers, about 8 baby carrots (healthy, right?), and chips with bean dip. And it's not like I was hungry - I had a massive Qdoba taco salad just two hours ago. So why are we - and why was I - doing this?

First, because the stomach is not a good or timely indicator of how much (or what) we should be eating, we look to external cues to guide our rationing process. For instance, we add to our plate or glass until it is full. That is, containers instruct our serving-size choices. Alternatively, we look around us and do what other people do. If they are munching on popcorn at the theater then by God, so will I! Case in point: 150 Chicago natives were asked how they knew they were full; their top three responses were "when my plate is empty", "when everyone else is through," and, no joke, "when the TV show I was watching ended." Contrast this with an identical survey of 150 Parisians: "when I feel full", "when the food no longer tastes good to me," and "when the food is cold." You draw your conclusions on this one, folks.

Professor Wansink outlined three food and eating myths: that bowl size does not instruct serving size, that we know when we are full, and that we know what food we like to eat. It is not that unusual to conclude that a bigger plate leads to larger portions. However the professor takes this a step further - he selected 60 graduate students and lectured them for 90 minutes EXCLUSIVELY on how larger serving sizes are a result of bigger containers. In a covert test following this direct and comprehensive education, those grad students with bigger bowls nevertheless ate 53% more than their counterparts. Similarly, he demonstrated that on average people pour 77% more on short, wide glasses than on narrow, tall glasses with the same volume. He did this test with many bartenders, with the exact same results. We pour to fill up the glass - that is our cue, not the objective measure of what portion should be consumed. (Note to self: check for short, wide bar glasses before ordering a whiskey on the rocks.)

As for the "we know when we are full" myth, Professor Wansink conducted a study in which he created a "bottomless" soup bowl that unbeknownst to the subject slowly re-filled his or her bowl. First, and most interesting to me, was that only 2 of 160 actually noticed that the bowl was not becoming less full as soup consumption was quite obviously taking place. Second, after 20 minutes, those with the bottomless soup bowl had eaten 77% more than those with regular bowls and reported IDENTICAL feelings of hunger. In other words, after eating almost twice as much food, they claimed to feel the same as those who had eaten far less!

His point with the "I know what I like" myth is that our tastes are in fact quite suggestable. In one study, he put chocolate syrup into vanilla yogurt and packaged it with a picture of a strawberry on it. All of his subjects readily accepted and spoke to the "strong strawberry yogurt flavors" in the chocolate yogurt. Similarly, at a mock restaurant he served 2 Buck Chuck (a horrendous, cheap wine good for only two things: getting you drunk and giving you a hangover) disguised as either a "California Cabernet" or a "North Dakota Cabernet." The descriptive cues and associated expectation of the California Cabernet resulted in a dramatic difference in results: California drinkers ate more, ate longer, gave the meal better ratings, and said they were more likely to come back than the North Dakota drinkers. Across many studies he has shown that by raising expectations, people actually believe things taste better. Put simply, adding candles and nice plates WILL make your date think you're a better cook (assuming of course that you don't serve her raw chicken).

So how to correct these sneaky overeating cues and impulses? If you think his solution is to get a gym membership, think again. He found that on average, most people gained a few pounds after starting an exercise program. This was not because people were building muscle - rather it was due to calorie compensation. People felt deserving of further indulgences as a result of working out, and consistently overestimated the number of calories they burned. On average people ate 28% more than they did before their work-out programs, but only burned 18% more calories!

He did, however recommend changing your environment, which he claims is much easier than changing your behavior. In other words, get rid of your short/wide glasses and buy smaller bowls. Alternatively, move your chocolate a few feet away rather than keeping it right in front of you and relying on your ability to say "no" fifty times without indulging. He also recommended against eating family style meals, and suggested putting serving bowls in the kitchen as opposed to on the table.

Will I change anything now that I learned more about the duplicitous nature of food consumption psychology? Probably not, but you should.

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