Stalking the truth about celery’s caloric impact

You burn more calories chewing and digesting celery than you take in by eating it, making celery a “negative calorie food.”

Fact: Although celery is one of the lowest-cal foods on the market, most experts agree you will still gain calories — a small amount — by eating it.

Celery is 95 percent water and high in indigestible fiber, so a single stalk has only 8 to 10 calories. There hasn’t been a hard scientific study that shows how much energy you expend when you eat a stalk of celery, but Dr. Donald Hensrud, a preventive medicine specialist at the Mayo Clinic, said chewing and digesting all the food the average person eats in a day only accounts for 5 to 10 percent of that person’s daily energy expenditure. In short, chewing and digesting aren’t high on the list of activities that will help you lose weight.

The dubious label “negative calorie” has sometimes been awarded to other fruits and vegetables that have high water content, including watermelon, cucumbers, beets, lettuce and citrus fruit. In truth, “low-cal” is a better descriptor than “nocal.”

And dieters beware: Research shows that the mere presence of these fruits and vegetables on your plate can lead you to believe you’re eating fewer calories than you actually are.

In a 2006 study from Northwestern University, 934 people viewed pictures of meals and estimated the number of calories each contained. Some respondents were shown photos of “unhealthy” main dishes like a hamburger, or a meatball and pepperoni cheesesteak. Others were shown the same main dishes, but this time paired with a “healthy” side dish, like an apple or carrot and celery sticks.

Even though the main dishes combined with the side dishes clearly contained more food and, therefore, more calories, the respondents guessed the combo meals had 43 fewer calories on average than the main-dish-only meals.

Researchers in a 2007 Cornell study had participants consume 1,000-calorie meals at Subway, which markets itself as a healthy restaurant, or McDonald’s, which does not. The diners weren’t told the true calorie counts of their meals but, when asked to estimate, both groups undervalued the caloric value of what they’d eaten. The Subway group’s average guess (585 calories) was 21 percent lower than the McDonald’s group’s (744 calories).

A related Cornell study showed that Subway diners were more likely to order large or non-diet sodas and cookies than McDonald’s diners. Subway diners, the researchers concluded, believed their “healthy” sandwich meal justified treating themselves to unhealthy drinks or desserts.