The Truth About Negative Calorie Foods

What exactly are “negative calorie” foods? Rumor has it that some foods, such as celery or lettuce, contain so few calories that you burn more calories digesting them than you gain eating them. Some even go so far as to say that the chewing process alone burns more calories than are actually in the food.

Negative calorie foods have been under scrutiny by researchers. It turns out that chewing foods burns, on average, about 5 calories an hour. Since each stalk of celery contains about 8 to 10 calories, it would seem that they do not, in fact, contain these “negative calories.”

On the other hand, research has not yet been completed on how many calories it actually takes to digest the celery – for our bodies to push the celery down the esophagus and break it down. It’s possible that it does take more than 8 or 10 calories to digest a stalk of celery, especially because celery contains a substance called cellulose. Cellulose is a fiber that the human body cannot break down, but it is unknown how many calories the human body expends while trying.

So are negative calorie foods really the key to weight loss? Unfortunately, they’re not the silver bullet that many believe. Even if digesting them does use up more calories than you gain by eating them, you won’t be losing more than a few calories in the process. It takes hundreds of calories to lose even one pound, so the small lack of calories won’t do much to put a dent in your weight loss goal.

At the same time, there’s one aspect of this hype that contains a grain of truth. Negative calorie foods can take the place of less nutritious and more fattening foods. Instead of snacking on potato chips, grab a crunchy stalk of celery. Avoiding the potato chips and filling up on the celery will lead to weight loss – even it’s not because of the celery’s negative calories.

http://www.nytimes.com/2006/07/25/health/25real.html?_r=1