Scientists unmask mythical foods such as celery require more calories to digest than they contain

It has long been claimed that some foods contain more calories to digest than what they contain.

But research has now suggested that food with & # 39; negative calories & # 39; as they are branded is nothing more than a myth.

Lizards chowed down on celery meals in what is considered one of the first studies to test the theory.

The reptiles retained about a quarter of the food's calories after digestion and excretion – creating the idea that so-called & # 39; negative calories & # 39; to exist.

Celery is only one food that is considered negative, in addition to cucumber, lettuce and broccoli.

Dieters are a fan food such as celery because it & # 39; negative calorie & # 39; food is. But researchers at the University of Alabama showed that lizards contain about a quarter of the calories in celery

Dieters are a fan food such as celery because it & # 39; negative calorie & # 39; food is. But researchers at the University of Alabama showed that lizards contain about a quarter of the calories in celery

The study, led by Katherine Buddemeyer of the University of Alabama, used a group of bearded dragon lizards.

Their metabolic rate – how much energy is needed for the body to perform basic functions – was calculated.

The lizards were given diced celery meals equal to five percent of their body mass – something they would like to eat as part of their omnivorous diet.

Faeces and urine samples were collected after they ate to determine how much energy was lost.

The findings showed that the lizards used about 33 percent of the calories in the meal for digestion and about 43 percent were excreted.


The basic amount of calories that an average adult needs per day is 2,000 kcal for women or 2,500 kcal for men.

This is based on the amount of energy that the body needs to perform basic functions and to walk and work all day.

People who train a lot need to eat more calories to feed their efforts, and young people and children also burn more energy.

If you eat more calories than you burn per day, you will get fatter.

If you eat fewer calories than you burn, you will lose weight.

Foods that are processed and contain a lot of carbohydrates, sugar and salt have a higher number of calories than fresh fruit and vegetables.

Examples of calorie counts include:

  • A McDonald & # 39; s Big Mac contains 508kcal
  • A KitKat with two fingers contains 106 kcal
  • A banana contains 95 kcal
  • An apple contains 47kcal

Source: NHS

That meant the animals retained around 24 percent of the energy of the meal – however, the calories were still a small amount.

The authors wrote: & # 39; By evaluating these energy components, we determined bearded dragons to experience a net gain in energy from their celery. However, this gain is quickly canceled out by the resting metabolism of the lizard. & # 39;

Although the study looked at only one animal, the researchers made a few assumptions about how this could be translated for humans.

& # 39; The same undoubtedly applies to people & # 39 ;, they said in the report of their findings published on bioRxiv.

& # 39; Those foods advertised as negative calories generate a net energy saving; however, this gain is quickly eliminated by the body's own basic metabolism. & # 39;

The researchers used the example of a 132-pound (60 kg) woman to suggest that people would retain around 19 to 50 percent of the calories from this food.

This assumes that 25 percent of the energy is used for digestion and absorption of food, five percent is lost in the urine and 30 percent in the stool.

A five percent meal of a woman's body mass – the same one given to the lizards – would correspond to 6 pounds of celery, which the woman would not give any activity for six hours.

That's why the researchers came to the conclusion that no one could eat the huge volume of low-calorie foods to keep functioning, but it makes them an ideal food to help with weight loss.

The researchers wrote: & # 39; The central goal of most & # 39; s programs to lose weight is to achieve a negative energy balance.

& # 39; Instead of such foods as & # 39; negative calories & # 39;, it would be more accurate to label these foods as & # 39; negative pitch & # 39; pitch, the consumption of which promotes a daily negative energy budget and therefore weight loss. & # 39;

In essence, low-calorie foods will not consume more energy than they contain, but they can easily be burned quickly.

The study has been submitted to the Journal of Experimental Biology and is currently being assessed, according to Live Science.

Dr. Sarah Brewer, nutritionist and medical director of Healthspan, accepted that there was & # 39; nonsense & # 39; is about & # 39; negative calorific & # 39; foods.

She said, however, that this study does not confirm that anyone can use more calories to burn a food than it contains.

She said: & # 39; It would be great to refute this theory, but this study does not, because it was done in lizards.

& # 39; Lizards are cold-blooded and need to get their warmth for the sun and their metabolism is very different from that of humans.

& # 39; People are warm-blooded and generate their own heat, and therefore they would use a significant amount of calories to do that. Unfortunately, this research does not really occur to me. & # 39;