You may have heard people say that celery has negative calories, which means eating celery burns off more calories than your body absorbs after eating it. While celery is a very low-calorie food and an excellent choice when you're trying to achieve or maintain a healthy weight, it isn't necessarily a "negative calorie" food.
Calories in Celery
Celery provides about 6 calories in each medium-sized stalk, according to the U.S. Department of Agriculture National Nutrient Database. The same portion of celery contains about 1 gram of total carbohydrates -- including 0.6 grams of fiber. Fiber isn't fully digested or absorbed by your body, according to the University of Massachusetts. However, the negligible number of calories provided by protein, sugar, and fat in celery are absorbed and used by your body.
Thermic Effect of Food
The number of calories your body burns by eating and digesting food, called the thermic effect of food, is about 10 percent of your body's total daily energy expenditure, according to a 2007 issue of the Journal of Applied Physiology. Therefore, if you're expending -- and eating -- 2,000 calories in a day, your body burns about 200 of those calories eating a digesting food. Therefore, if you're eating a 6-calorie, medium-sized celery stalk, your body will burn almost 1 calorie eating and digesting that stalk.
While celery is a very low-calorie food, it likely doesn't provide you with negative calories. Mayo Clinic suggests that while it's theoretically possible for negative-calorie foods to exist, there are no reputable scientific studies that prove certain foods cause "negative calorie" effects. In fact, protein is the macronutrient that causes your body to burn the most calories, according to a review published in 2008 in the American Journal of Clinical Nutrition. Furthermore, while fiber isn't absorbed by your body, a medium-sized celery stalk only contains 0.6 grams of fiber but provides 6 total calories. Chances are your body will absorb at least some of the calories celery provides.
An experienced health, nutrition and fitness writer, Erin Coleman is a registered and licensed dietitian and holds a dietetics degree from the University of Wisconsin-Madison. She also has worked as a clinical dietitian and health educator in outpatient settings. Erin's work is published on popular health websites, such as TheNest.com and JillianMichaels.com.