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Do calories with a reverse effect exist?
Table of Contents
1. What are Calories?
The energy value provided on the packaging of a product determines the number of calories it contains, allowing one to estimate the amount of energy it will provide. This is significant when losing weight, but not exclusively so. It enables the estimation of the quantity of food that can be consumed in a day to ensure health. From a physics perspective, calories are simply the amount of heat that is released after the digestion of individual nutrients. The energy value can be divided into net and gross. The former is more precise as it takes into account the energy that the body can fully utilize after all metabolic processes have taken place. The term "empty calories" may also be encountered, which does not refer to food with low energy, but rather to that which provides few valuable vitamins and components, but many calories. These are considered less nutritious products, potentially hazardous, as their regular consumption can lead to a significant increase in body weight and, in the long term, inadequate supply of valuable substances.2. Definition of negative calories
According to the negative calorie concept, there is a special group of products that allow the human body to consume more energy after eating than the products provide, enabling the burning of not only the calories from a certain product but also the excess ones. Advocates of the negative calorie diet claim that it is a great method for weight loss. Furthermore, it is very simple and enjoyable, as it only requires increasing the consumption of products from this special list to burn off the energy surplus.3. Products with potentially negative caloric balance
Among the most popular products that have the potential to help burn more energy than they themselves provide are: - root celery, - salads, - cucumbers, - watermelons, - grapefruits, - tomatoes. These are products with a high water content and very low fat content, so their caloric value is extremely low but not zero. Each of the mentioned products provides a certain amount of calories, but not more than 40 kcal/100 g.4. Negative calories from a scientific perspective
The theory of negative calories has piqued the interest of not only overweight individuals but also scientists. The concept seems somewhat unrealistic, so researchers decided to investigate it further. K. M. Buddemeyer and colleagues used national celery in their analysis, which is a good example of a product with allegedly negative calories due to its low calorie and high water content. The study was conducted on bearded dragons (Pogona vitticeps), whose digestive, absorption, and metabolic processes are similar to those of humans. Researchers found it too difficult to conduct the experiment on humans, so they opted for bearded dragons, which are easier to control.5. Zero calorie products
Products labeled as "calorie-free" should contain less than 5 kcal per serving. In many cases, they contain substances that are not metabolized by the body, so they do not provide any or only a small amount of calories. However, there are no scientific studies to confirm their negative effects on the body. The only exception is water, which can increase food thermogenesis and metabolism between meals. However, the changes observed in studies (C. M. Brown et al., 2006) are so minimal that it is difficult to confirm that water actually helps in weight loss. It usually increases the number of burned calories by a maximum of 24-60 in the case of severe dieting.6. Theory of negative calories - another false myth
The theory of negative calories, while fascinating, has not been substantiated by any scientific research, and therefore cannot be used for weight loss purposes. Products that theoretically do not provide calories but instead help burn them are extremely valuable dietary components due to their low energy and high fiber content. Furthermore, they are an important source of other nutrients, such as vitamins and minerals. Instead of relying on magical methods, it is wise to ensure an appropriate energy deficit in the diet, so that weight loss can be achieved even when consuming favorite snacks and meals. Regular physical activity should not be neglected either, as it increases the body's energy demand. Drinking water is also a good habit, not because of its supposed calorie-burning properties, but because it plays a crucial role in many processes in the body.
