Fat burners are one of the most popular types of sports supplements. From the point of view of manufacturers, the principle of their action is based on accelerating metabolism, blocking the feeling of hunger, and normalizing metabolic processes in the body – which, theoretically, should lead to weight loss.
The main ingredient in legal fat burners is caffeine, which speeds up your heart rate and suppresses your appetite. Stronger substances are prohibited by law because they can be addictive and have a long list of contraindications.
Fat burners – what are they?
Fat burners are a category of sports nutrition designed to reduce body weight. However, contrary to the name, they cannot literally “burn fat”, and weight loss with their help is achieved solely by increasing activity levels and slightly blocking appetite.
However, only a few sports fat burners can influence even these parameters – while the vast majority of supplements contain large doses of caffeine and secondary components with a very controversial evidence base.
It is important to understand that fat burners are not drugs. That is, they are not tested for compliance with safety standards and for the absence of contraindications. That is why manufacturers use abstract phrases such as “improves”, “promotes”, and “normalizes”.
What is the working principle?
Substances that have evidence as fat burners are caffeine, ephedrine, methylhexanamine (DMAA), and phenylpropanolamine (PPA). Taking them affects the central nervous system of the body and gives a surge of vigor – as well as euphoria and the addiction associated with it.
However, the effectiveness of caffeine and other “natural” substances is quite low (plus, tolerance to caffeine quickly develops), and ephedrine is prohibited in the Russian Federation as a precursor drug since it can be used to obtain a substance similar to amphetamine.
Separately, it is necessary to mention growth hormone. Although it is widely believed to be a safe supplement for burning fat and gaining muscle mass, many scientific studies suggest that it accelerates the aging process and is statistically linked to earlier death.
Sports supplements for weight loss
The division of sports fat burners into types is arbitrary. Typically, drugs contain several active components that have a synergistic principle of operation. Some of them suppress appetite, others increase body temperature and increase sweating:
Thermogenics. They accelerate metabolism by increasing body temperature and activating the central nervous system. They have a large list of contraindications and side effects (irritability, sweating, tachycardia). Often close to amphetamines in molecular structure and mechanism of action.
Appetite suppressants . Most supplements that fall into this category of fat burners are essentially thermogenics. It is necessary to understand that there are no drugs that significantly reduce the level of appetite, but do not affect other metabolic characteristics.
Diuretics. Like other laxatives, diuretics stimulate intestinal motility and inhibit the reabsorption of water. The result is a temporary reduction in weight and numbers on the scale due to a decrease in the amount of fluid in the body. Typical side effects are diarrhea and increased sweating.
Calorie blockers. In theory, such fat burners should interfere with the absorption of food nutrients, helping to reduce calorie intake – for example, turmeric. However, in practice, their effectiveness is low – with the exception of pharmaceutical drugs that impair the absorption of fats during digestion.
Means for improving metabolism. They are able to reduce weight and show fat-burning effectiveness exclusively in cases of impaired metabolism, normalizing it. They represent a large category of various substances – from L-carnitine to drugs for normalizing the thyroid gland and vitamins.
New generation fat burners
If the principle of operation of “classical” fat burners is based on activating the central nervous system, increasing the heart rate and increasing sweating (which, in theory, helps to burn more calories), then the latest generation of drugs try to influence the hormones of hunger and satiety.
In particular, we are talking about the effect on ghrelin and leptin – obese people often have resistance to leptin (which negatively affects satiety mechanisms and provokes overeating). However, as of 2020, studies of such drugs have only been conducted on animals.
Theoretically, lowering ghrelin levels by taking a certain drug should turn off hunger mechanisms—preventing overeating. But in practice, this can lead to increased sensitivity to the hormone – causing long-term negative consequences.
Which fat burner is better?
Speaking about the best fat burners, it must be noted once again that none of them are capable of literally “burning fat.” Weight loss with the help of such supplements can be achieved solely by accelerating general metabolic processes – and against the background of diet and exercise.
In other words, it is impossible to lose weight just by taking pills – and without normalizing your diet or regular exercise. Moreover, even if a fat burner speeds up metabolism, we are talking about single percentages – that is, giving up a glass of cola or sweet juice will have a comparable effect on the calorie balance.
Hidden dangers
Dietary supplements, unlike full-fledged medications, are not tested for safety and for combination with chronic diseases. Before going on sale, fat burners undergo only a formal test to ensure the absence of poisons and toxins – the long-term effect on the body is not considered.
For example, in the United States, regulators have revoked licenses for fat burners numerous times following deaths caused by its use. However, manufacturers often do not even change the brand, but only change the composition, replacing the “undesirable” substance with another herbal analogue.
Fat burners are a key category of sports nutrition that has an extremely controversial evidence base with a complete lack of information about the long-term consequences of taking it and possible contraindications. Plus, the main ingredient in most fat burners is regular caffeine.