It seems like a paradoxical term doesn’t it; ‘Negative calories’? Yet, from time to time we do hear the term negative calories leaving us wondering what this actually means.
Put simply, negative calories are contained in those foods that use up more calories to get digested than they actually contain.
Celery or grapefruit are very often touted as weight loss therapies and many people say that it takes the body more calories to actually digest these items than they actually contain. Supposedly some foods cause a caloric deficit by the simple act of eating them.
So by that token, if one wanted to lose weight, they could simply subsist on celery and grapefruit for a few days and get rid of the pesky pounds.
And so by eating a celery stick will you have automatically burned some calories to actually cause a caloric deficit? Well not quite! If only weight loss were that simple.
Yes these and other foods do assist in weight loss but not because they are negative calorie, rather it is because they are low calorie foods that may tend to make you feel full even without being calorie laden.
The argument made by proponents of negative calorie in favor of these foods is that the Thermic Effect of the food is greater than its caloric content. And what is thermic content?
It is, according to Wikipedia, the increment in energy expenditure above resting metabolic rate due to the cost of processing food for storage and use and is one of the components of metabolism along with the resting metabolic rate, and the exercise component.
However, this is simply not scientifically borne out, and neither is there any concrete evidence to support it. There are a lot of negative calorie diets out there that are supposed to be working miracles to make us all lose a bunch of weight; where these are advertised you will also see glowing testimonials from people who have successfully used the method to shed their excess weight. However, there is no proof that negative calorie foods do work in the way that they are said to do.
Celery is said to be a negative calorie food, however, it takes only about 10% of the calories contained in a stick of celery for us to actually digest it.
Certainly it is true that certain foods are low calorie, and certain foods undoubtedly will use up more calories to be digested than others, however to claim that some foods actually burn more calories than they contain is actually just not true!