How do fat burners work? Learn about their mechanisms of action
There are many extreme opinions about fat burners. Some are based on expert knowledge, some on one's own experience, and some on mere imaginations and joyful creativity. The most valuable are, of course, the former. It is worthwhile to gain a theoretical background about the operation of fat burners, so that you can reasonably choose products for yourself, with the right mechanism of action and effectiveness.
What are fat burners?
A fat burner can be called a substance or a complex of substances that exhibit any of the following properties:
- increase in fat metabolism,
- increased energy expenditure,
- reduced fat absorption,
- increased fat oxidation during exercise,
- reduced appetite,
- increased long-term adaptations that promote fat metabolism.
Fat-burning complexes also include ingredients that act indirectly, for example by supporting thyroid function or normalizing glycemia.
The list of potential fat burners is long and growing. Unfortunately, it is lengthening faster than the list of studies analyzing their effects, due to the huge demand in society. The growing market for fat burners is a response to the wave of obesity flooding the world. More and more people need support in normalizing their body weight, but this does not mean that one should act blindly. It's worth learning about the mechanisms of action of fat burners before choosing something for yourself.
Division of fat burners by mechanism of action
The following classification is not official (such probably does not exist), but it divides the mechanisms of action into the most popular and significant ones.
Stimulants
The most popular and attractive group of substances. They are highly desirable because the effect is instant and very pronounced, although not always strictly fat burning. Most complex fat burners are precisely stimulants due to their caffeine content, and sometimes other, more potent substances.
The effects of stimulants are multifaceted. First, they inhibit fatigue and significantly increase motivation for action. In fat burning, it is this action that is crucial - to get rid of spare fat, we need to move so that working muscles can burn it. Training volume is the most important parameter in weight loss, right after the caloric balance of the diet.
Many stimulants have a proven effect on increasing the rate of fatty acid oxidation during exercise. Their energizing effect is due to increasing the release of catecholamines, which have a strategic function in fat burning by activating adrenergic receptors located on the membranes of fat cells.
The most popular, because relatively safe and legal, stimulant is caffeine. Also safe, but less popular (because much more expensive) are theacrine and methyloliberine. On a slightly higher shelf will be yohimbine, rauwolscine and synephrine. Burners from the gray market, mainly American brands, also contain much stronger and not so safe substances, such as DMAA, DMHA and various types of phenethylamine derivatives, which with their effects already approach narcotic substances. Stimulants illegally used to support fat burning include ephedrine, amphetamine and fentermine.
Appetite blockers
Appetite suppression is the domain of most stimulants, which is another advantage of the previous group. However, there are several non-stimulants that have some effect on appetite suppression.
5-HTP from Griffonia simplicifolia - this is an effective precursor of serotonin, the so-called happiness hormone. In supplementation it is mainly used to improve mood and support sleep quality, but there are quite a few reports in the literature of its effectiveness in appetite reduction. 5-HTP is used solo, and sometimes (rather rarely) it is also found in the formulations of American complex burners.
Saffron extracts - another supplement whose main function is to improve mood, and appetite suppression is more of a side effect. Nevertheless, it has been documented, and the main use for appetite suppression is Satietrim's patented saffron extract.
Ginger extract - has rather less potency than the previous two, but there are also reports of appetite reduction through supplementation of ginger extracts in scientific publications.
Chromium, for example, is also often mentioned in this category, especially for reducing the desire for sweet tastes. Reports here are mixed, and effectiveness may depend mainly on baseline chromium status (whether we are deficient) and the state of sugar management.
Thermogenics
This group includes the aforementioned ginger, but also extracts of green tea, black pepper (piperine), cayenne pepper (capsaicin) and many other warming ingredients. Caffeine and other stimulants also have thermogenic effects. Also attractive in terms of fat burning is forskolin, which has thermogenic effects, but can also enhance the burning effects of other substances. Even more interesting is fucoxanthin (a carotenoid from seaweed), which can increase the amount of brown adipose tissue, the one involved in regulating body heat.
Thermogenics are substances that intensify the process of so-called thermogenesis, that is, the production of heat by our body. To maintain a constant body temperature, the body must use energy substrates on an ongoing basis, the burning of which generates heat. In a way, thermogenics can mimic exposure to a cool environment, forcing the body to burn energy a little faster for thermoregulation.
Many natural thermogenics have sensational health benefits. The lion's share of them are natural extracts that, in addition to thermogenic substances, also contain a multitude of flavonoids with interesting and diverse effects.
β2 adrenergic receptor agonists
In this group, mainly drugs with weight reduction as a side effect are present. These are mainly clenbuterol (very popular in sports doping) and salbutamol (an asthma drug). In supplements (again, mainly those from the US) there is a similarly acting hygenamine.
β2 receptors are located, among other things, on the membranes of fat cells. Their activation triggers a cascade of events that release energy stored in these cells. Substances in this category are banned by the World Anti-Doping Agency (WADA) and are not inert to health.
Metabolism regulators
This is a fairly general category, into which can be drawn various substances with quite different effects. It could be certain vitamins and minerals that are involved in metabolic processes. It can also be, for example, the popular l-carnitine, which participates in the transport of fatty acids to the mitochondrion. And also choline, which participates in fat metabolism. Substances in this category, for the most part, are very friendly to health, although their effect specifically on fat burning is usually rather symbolic and dependent on other factors.
Is it worth using fat burners?
Of course, if they are properly selected. Both the action and the effect on health of different burners vary significantly. Choosing a random burner based on the marketing description alone can be met with disappointment, but sometimes also, in the worse case, with side effects. However, by choosing a burner to suit your needs and conditions, you can achieve good results, often with health benefits.
It is also worth remembering that the classics: caffeine and green tea extracts have the widest support in scientific research. Other substances, though some incredibly promising, should usually be supplements to caffeine and green tea, to complement their effects.
Below are examples of comprehensive dietary supplements with reasonable formulations and good user reviews:
Sources:
- Jeukendrup AE, Randell R. Fat burners: nutrition supplements that increase fat metabolism. Obes Rev. 2011 Oct;12(10):841-51.
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