Venture: Does this salad make me look skinny?

October 17, 2011

By Dan Weissmann

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(Flickr/Calamity Hane)
Yum: Pork burger and salad!

Your life is a tapestry of decisions: where you live, where you work, who you love, what you buy. And even what you eat. 

If you're trying to watch your weight, Alexander Chernev has some bad news for you: Dieting makes you fat.

That's how he puts it in his new book, The Dieter's Paradox - but I would put it a little differently:  Watching your weight makes you stupid about food. Chernev is a research psychologist, and he teaches marketing at Northwestern University's Kellogg School of Management. He studies how people make decisions, like: How do I choose from among a zillion different investment vehicles? Or: How do I decide what to eat?

So for one study, he took 900 people and showed them pictures of food, and asked them to guess how many calories were in each picture. Half of them were shown pictures of unhealthy stuff-- like a cheeseburger. The other half were shown the same unhealthy things-- but each one was paired with something more wholesome, like a side salad with no dressing.

And when he asked them to guess the calorie content, the people who saw the junk-plus-salad combo guessed lower than the people who saw the junk food alone.

Later, he asked people: So, do you think salads take away calories or something? 

And they said, no, but, Chernev says they added: "I can totally see how most people will say that adding a salad reduces the calories of the burger."

Chernev says this "side-salad delusion" is the result of a well-documented phenomenon called the halo effect: Basically, having one thing going for you makes people tend to give you the benefit of the doubt on other things, too.

So, having a healthy veggie on the plate makes the burger itself look less unhealthy.

Chernev says the underlying principle is a universal tendency to use mental shortcuts-- psychologists call them "heuristics" but you could also call them "stereotypes."

Usually, they're useful, because they let us make a lot of decisions quickly.

Just not always so accurately. Especially if we're on a diet. In that side-salad experiment, Chernev isolated the results for people who said they were watching their weight. And it turned out they were stupider than the rest of the group. Everybody knocked calories off the cheeseburger-plus-salad combo-- but the dieters knocked off more than twice as many calories as everybody else.

Chernev thinks dieters are more suceptible to halo effects because a lot of diets work by dividing the world of food up into "vices"-- like cheeseburgers-- and "virtues" -- like salads.

And a little virtue cancels out some vice.

By the way: The science of all this is being used against you.

When I asked Mary Valentine if these results sounded familiar, she said, "This is exactly why I'm going to hell. It's not the only reason I'm going to hell, but it's definitely the number-one reason I'm going to hell."

Valentine is a food stylist: She gets food ready to be photographed for cookbooks and food magazines, and advertisements.

Say a client wants a shot of four deep-fried fish filets-- each with 23 grams of fat

"But as long as there's a little salad in the background, your brain is like, 'There's something green, so it must be OK to eat,'" Valentine said. "It's like thinking a spinach salad is the same as a spinach pizza."

It's not just cozying up to a veggie that casts a low-cal halo over fattening foods. In his research, Chernev found that just describing something as fat-free, or organic, or even as having some totally non-nutrition-related virtue-- like being made by a company that donates profits to charity--causes us to unconsciously knock some calories off our estimates.

I thought about local businesses where I'd be likely to make this kind of mistake.

At its Devon Avenue location in Edgewater, UnCommon Ground has an organic farm on the roof. Right next to the solar panels.

I have a hard time thinking that anything I could order there-- like, say, macaroni and cheese-- could possibly be bad for me.

"It's funny, because I can see how we all do that," UnCommon Ground co-owner Helen Cameron said.  "But it's totally wishful thinking. You will have the macaroni and cheese, and it will be made with butter, and real Wisconsin local cheese-- and then there will be a nice coleslaw on the side, but it's going to have the calories that it has."

Chernev found other ways we fool ourselves when we're dieting too.

Like rewarding ourselves with big indugences-- a serving of tiramisu with lunch--after making small "sacrifices"-- like passing up a biscotti with our morning coffee. 

He's got a million of them.

But why is this business professor doing research on dieting, anyway?

He says that, for someone interested in how people make decisions, food is a natural.

"Food decisions you make every day, and you make multiple food decisions-- what you're going to order, how much you're going to order, whether it's going to be diet, non-diet, what combinations, how much to eat-- so here is plenty of decisons, and some estimate that it's as many as 200 decisions a day," Chernev said.

One more piece of bad news: Don't think that listening to this story is going to help you much.

Chernev says that while he was working on The Dieter's Paradox, he ate more crap--cookies, candy bars, cheeseburgers--than he'd ever eaten in his life.  

So, what was he thinking?

"I can allow myself to eat whatever I want, because I know more about this, and I can control myself much better-- at least theoretically."

In other words: Even learning about how dieting makes you stupid does not actually make you smarter.

 Music used in the audio version of this story:

* "Fender Bender" by Kid Koala (from the album Carpal Tunnel Syndrome)
* "Brilliant Corners" by the Kronos Quartet (from the album
Plays Music of Thelonious Monk)