The Fairy Tale of Negative Calories

What a “negative calorie” diet promises sounds too good to be true: Lose weight and reach your desired weight by doing what is usually regimented in other diets: eating. So-called negative calories (sometimes also misleadingly called negative foods) are supposed to melt away superfluous kilos via diet, help you lose weight and thus lead to the dream figure. The trick behind the diet with negative calories is allegedly that certain foods are said to have so few calories that they burn more calories through digestion than to supply the body.

Negative calories: Diet with a thinking error

But behind the diet “negative calories” hides a thinking error. In fact, there are some foods that contain very few calories and at the same time boost digestive activity through a high fiber content. These include many fruits and vegetables, such as celery. Celery has virtually no calories, but is rich in fiber, which is digested by the body with a high energy expenditure.

Nevertheless, the energy balance cannot be negative. The energy required for digestion is already taken into account in the food and included in the calorie count. A stick of celery, for example, has ten calories and requires an energy expenditure of two calories for digestion. The calorie count is therefore given as eight calories, since eight calories remain for the body after digestion.

Food and negative calories

On average, about ten to twenty percent of a food’s calories are spent in digestion. So a residual energy for the body remains in any case. However, foods such as cucumbers, spinach, mushrooms or lettuce are negligible as energy suppliers anyway.

Diet experts recommend the consumption of vegetables (for example, during diets) to prevent a feeling of hunger and to ensure the absorption of important vitamins. However, their consumption does not contribute to additional weight loss.

The dietary effect of excessive consumption of fruits and vegetables and the avoidance of other foods is different: the body is simply supplied with too little energy. In order to still maintain its functions, it is forced to fall back on its reserves and convert them into energy, which can have a weight-reducing effect.

Balanced diet is important

In the long run, however, abstaining exclusively from fruits and vegetables is not healthy. That is why diets should be based on a healthy and balanced diet, which without question includes the consumption of fruits and vegetables. Above all, these foods should not be reduced to their low calorie count. After all, these foods contain a variety of essential vitamins and fiber, and represent a delicious side dish or appetizer, which is far from negative calories.