We often hear the refrain, “trust your gut.”  Unfortunately, doing so might just increase your gut, literally!  It happened to me this past year when I underestimated the amount of weight I let myself gain, assuming I could judge it by how my clothes felt.  What I didn’t take into account was the clothes I’d avoided because they felt a little snug. Without the reality of stepping on the scale, I could fool myself into believing what I wanted to believe, that it was just a pound or two, which I would easily take off in the following month.  When I finally did step on the scale, it snapped me out of my illusion and taught me a lesson I seem to keep needing to learn. When it comes to judging myself and my habits, I am not terribly accurate.

Then I saw a study in the New York Times last week that made the sting of my misery a little less with company.  It was actually an article about the effects of exercise on weight loss. The researchers in this experiment compared two levels of exercise, one group burning 1500 calories a week and the other 3,000 calories a week.  What they found was that the higher exercise group did lose some weight, but that the lower calorie exercise group did not lose any weight, and some even gained a little! What they also found was that both groups ate more calories as a result of their exercise, about 1,000 extra calories. The difference than being that those who had exercised more had maintained more of the calorie deficit. But what got my attention (and my sympathy) was that each group had no awareness of their extra eating. According to the study, “Their food intake recall did not show differences in how they ate before the study and at the end,” states Kyle Flack, one of the researchers.  He concludes, “I think they just did not realize that they were eating more.”

Apparently our judgment tends to be skewed when it comes to our own perceptions of our behavior and from our desire to look good to ourselves and others. This is actually called “self-reporting bias” in the scientific literature. We tend to under-report behavior deemed negative (unhealthy eating) and over-report behaviors viewed as positive (such as exercise).  In order to compensate for this bias, nutritionists actually have developed a technique to more accurately reflect our eating patterns. It is called the 24 hour dietary recall method. It involves asking a respondent to recall everything they ate within the most recent 24 hours, typically from midnight to midnight.  Then, after the free recall, a structured set of follow up questions prompts the individual’s memory for foods they may have forgotten (the soda after work, the snack after dinner), and for more detailed information about ways in which the food was prepared and portion size. Through this method, much more accurate accounts of people’s food intake is obtained, and often explains why people had not been losing weight or bringing blood sugar levels down.  The only bad news for us at home is, the technique can take as much time as a half an hour!

24-Hour Food Recall Forgotten Foods
There are some foods that people tend to forget they ate.
 Did you have any crackers, breads, rolls, or tortillas that you may have forgotten about?
 How about any hot or cold cereals?
 Cheese added as topping on vegetables or on a sandwich?
 Did you have any chips, candy, nuts, or seeds?
 Fruit eaten with meals or as a snack?
 What about coffee, tea, soft drinks, or juices?
 Any beer, wine, cocktails, brandies, or any other drinks made with liquor that you may have forgotten?

I know, who the heck has that kind of time, let alone patience!  But the lesson for me, in looking into this issue, is the importance of objective tracking and feedback.  There are piles of research showing the inaccuracy of our memories, even for events we swear we could never forget.  So why would it be any different with food? So, if I want to keep from being a victim of my own self report bias, I’m just going to have to get real.  Indeed, I bought a scale and I’m going to remember to use it!