Opinion, Berkeley Blogs

On not blowing your diet after those long holiday weekends

By Rodolfo Mendoza-Denton

If you have ever been on a diet, you know how difficult it can be to restrain the impulse to eat, eat, eat. It almost seems like even beyond our normal tendency to eat, dieting -- when we're not careful-- can lead you to lose it and, ironically, eat even more.

In this post, posted right before another holiday (Easter), I talked about why counting calories is a really good way to stick to a diet. To summarize, counting calories, at a cognitive level, does two important things: a) it constantly reminds you of your weight-loss goal; and b) it changes the mental representation of that no-so-great-for-you food from "yummy" to "caloric bomb for the diet."

Following that post, an astute reader asked, "so, professor,how many chocolate eggs and bunnies did you consume?"

The answer was none... for about a week. I was feeling proud of my accomplishment, so I decided to reward myself with a little leftover treat from the holiday. The problem was that after that, I couldn't stop-- I kept eating and eating, and instead of a little treat, I ended up blowing my diet wide open. I fell off the bus, the road, and the hillside.

This experience reminded me of one of the most memorable research lectures I've ever heard. It was a talk at Columbia University by Todd Heatherton, a self-regulation researcher at Dartmouth. Dr. Heatherton described a study in which restrained and non-restrained eaters (essentially, dieters versus non-dieters) were brought into the lab to conduct a "taste test." The details are a little fuzzy (the talk, I think, was in 1998) but from what I remember participants were asked to provide ratings of how good a particular ice cream was. The ice cream was rich and decadent, and the participants were asked to finish a good portion before providing their ratings.

After the experiment was over, the participants were brought into a different room, and were told to help themselves to some other treats--cookies, I think-- that had purportedly been left over from another experiment. Dr. Heatherton showed a graph comparing the consumption of these "freebie" sweet treats among the dieters vs. non-dieters. The graph was absolutely striking-- whereas the non-dieters helped themselves to a few of these treats after having eaten the rich ice cream, the dieters ended up helping themselves to several times the amount that the non-dieters did. As the audience sat silent, amazed and trying to understand why this difference occured, Dr. Heatherton said simply,

-- We call this the "What The Hell" effect.

The audience roared in delight-- with that one phrase, everyone understood the psychological mechanism underlying the sudden, unrestrained eating among the dieters (at that moment, I think, my commitment to research psychology was cemented). The dieters had blown their diet with the ice cream, and this then led them to lose self-regulation at a subsequent, unrelated opportunity. The "what the hell" effect has been recently replicated by Janet Polivy and her colleagues in a 2010 paper (that paper is summarized well here). A write-up of this study in The Economistconcludes that this shows that diets don't work-- that is, dieiting makes you vulnerable to the What the Hell effect.

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Butthis conclusion is premature.No matter which way you look at it, eating one or two cookies is still better than eating nine or ten-- the amount of damage to your diet is proportional to the amount you eat.The reality is that dieting trip-ups, or the occasional treat, don't have to lead to a What the Hell effect.And simply knowing about this effect gives us an important self-awareness tool for recognizing when we are at risk for blowing our diet.

So if you've managed to resist temptation this holiday weekend-- good for you! And if you blew it, regroup and get back on your diet. It's OK to reward yourself or to trip up a little bit.Just keep in mind that these moments make you vulnerable to outright falling off the diet bus, so make a plan to stay on the bus-- for example, by dutifully entering even those indulgences into your calorie counter.

Cross-posted from Psychology Today; Copyright 2011 by Rodolfo Mendoza-Denton; all rights reserved.