Negative calorie foods
Stories from Physics for 11-14 14-16
Some diet regimes have suggested that dieters consume ‘negative calorie’ foods in order to lose weight. Theoretically, negative calorie foods require greater energy expenditure in digestion than is gained from their consumption, resulting in a net energy deficit. Celery is a commonly cited example of such a food. A recent study of celery consumption by bearded dragons suggests that the idea that celery is a negative calorie food is a myth, at least for these reptiles. It is reported that the lizards retained at least 24% of the energy in the celery they consumed.