Celery has negative calories
Celery contains approximately 6 to 14 calories per serving and has a thermic effect of only around 8%, far less than the 100% or more that would be needed for it to have a negative caloric value. No food has been shown to have genuinely negative calories.
What we know
The negative-calorie food concept holds that certain very-low-calorie foods require more energy to digest and process than they deliver to the body. Celery is the most frequently cited example, given its very low calorie content (roughly 6 calories per medium stalk, 14 per 100g cup) and high water content (about 95%).
However, the thermic effect of food (the energy cost of digestion, absorption, and metabolism) for celery is estimated at around 8% of the food's caloric value. This means that for every 14 calories in celery, the body expends roughly 1 calorie to process it, leaving a net positive caloric contribution. No food reliably reaches a thermic effect of 100% or more under normal eating conditions. Chewing alone adds a negligible few calories burned per hour.
The negative-calorie myth persists because very-low-calorie, high-fiber foods like celery can contribute to satiety and help reduce total caloric intake, which is genuinely useful in weight management. However, this is not the same as burning more calories than the food provides. A 2005 low-fat plant-based diet study found weight loss attributable to reduced energy density of foods, not to any negative-calorie effect.
Celery is a nutritious, low-calorie food and a good choice as part of a balanced diet, but it does not create a caloric deficit simply by being eaten.
Common claims
- Eating celery burns more calories than it providesFalse - thermic effect is only ~8%
- Celery has essentially zero net caloriesPartly true but not negative
- Negative-calorie foods are a proven weight loss toolNo evidence for negative calorie effect
- Dietitians recommend celery for its negative-calorie propertiesRecommended as low-calorie, not negative-calorie