Fat burner

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As a fat burner ( Engl. Fat "fat" and burn "burn") are substances which, among other things, promote the body's fat burning is said to have. Scientific proof of a benefit has so far only been provided for individual representatives (caffeine, green tea). There are fat burner diets that want to take advantage of this effect.

properties

Some natural fat burners are produced by the body. These include glucagon and the growth hormone somatotropin . Fat burners are also found in foods, and these supposedly include magnesium , linoleic acid and vitamin C , enzymes and L-carnitine , caffeine , green tea , forskolin , chromium , seaweed , conjugated linolenic acids and fucoxanthin .

Artificial fat burners are mixtures made from natural and synthetic substances that are taken in tablet form, as a powder or as a liquid in addition to food. They are used to aid in reducing body weight and in the context of bodybuilding . Sometimes, however, they contain substances the supply of which is legally restricted in Germany (e.g. ephedrine ) or which cause undesirable side effects. The immediate intended effects of fat burners have been questioned by many doctors and nutritionists.

theory

Some authors of diet books or guidebooks assume that the fat burning of the body can be artificially increased through the intake of suitable substances, independently of sport and exercise. This should be achieved through a changed metabolism , an increased body temperature , faster fat burning or more fat excretion . The recommended substances should be taken as a dietary supplement or with the help of special foods as part of a diet.

criticism

The main objections are:

  • Enzymes are made up of protein . They are denatured by gastric acid in the stomach and broken down by proteases in the stomach and intestines . They are then no longer effective.
  • The effect of L-carnitine is controversial. Most studies could not show any positive effect on fat burning, performance or muscle regeneration due to increased consumption of L-carnitine. The studies that showed an alleged effect were often flawed (due to their experimental design or placebo interpretation). Basically, the body is able to produce L-carnitine on its own, but takes in most of it through food (meat). L-carnitine transports fatty acids into the mitochondria of the muscle cells, so it is essential for the supply of energy (in the form of adenosine triphosphate ) from fats. However, the number of these cell organelles is decisive; it only increases as an adaptation to physical stress. In the opinion of the scientists at the Institute for Food Science and Ecotrophology at the University of Hanover, the transport of fatty acids into the mitochondria is at its maximum at a physiological (normal) concentration of L-carnitine.
  • The intake of hormones is harmful to health. The additional administration of thyroid hormones produced an artificial hyperthyroidism (Hyperthyreosis factitia). The result can u. a. Racing heart, high blood pressure and sweating.
  • Caffeine and guarana must be consumed in large quantities to increase energy burn. However, high doses lead to health problems such as palpitations and tremors.
  • The importance of growth hormone for adults has been questioned.
  • Chromium is contained in some fat burner preparations and is said to have a positive effect on the carbohydrate and fat metabolism. In fact, this effect has not been proven. In some studies, chromium was ascribed a mutagenic and thus carcinogenic property. The consumption of preparations that contain chromium for the purpose of optimizing the metabolism is therefore not advisable.
  • Taking ephedrine (especially if the dosage is incorrect) can lead to severe side effects. Ephedrine is on the doping list .
  • The product development of food supplements is driven by industry, not nutritional science.
  • The claimed properties are often not proven.
  • Case studies have reported isolated cases of illness and death. Herbal supplements containing usnic acid can cause liver failure . One death from caffeine as a fat burner has been reported.

Individual evidence

  1. ↑ a b c d e A. E. Jeukendrup, R. Randell: Fat burners: nutrition supplements that increase fat metabolism. In: Obesity Reviews . Volume 12, Number 10, October 2011, pp. 841-851, ISSN  1467-789X . doi : 10.1111 / j.1467-789X.2011.00908.x . PMID 21951331 .
  2. ↑ Jeremy M. Berg, John L. Tymoczko, Lubert Stryer: Stryer Biochemistry . 7th edition, Springer-Verlag, Berlin / Heidelberg 2013, ISBN 978-3-8274-2988-9 .
  3. ↑ M. Saldanha Aoki, AL Rodriguez Amaral Almeida, F. Navarro, LF Bicudo Pereira Costa-Rosa, RF Pereira Bacurau: Carnitine supplementation fails to maximize fat mass loss induced by endurance training in rats. In: Annals of nutrition & metabolism. Volume 48, Number 2, 2004, pp. 90-94, ISSN  0250-6807 . doi : 10.1159 / 000077043 . PMID 14988638 .
  4. ↑ Entry on ephedrine on dopinginfo.de. Retrieved August 10, 2012 .
  5. ^ A. Hahn, A. Ströhle, M. Wolters: [Dietary supplements and functional food for weight reduction - expectations and reality]. In: MMW Advances in Medicine. Volume 145, Number 42, October 2003, pp. 40-45, ISSN  1438-3276 . PMID 14655443 .
  6. ↑ RK Yellapu, V. Mittal, P. Grewal, M. Fell, T. Schiano: Acute liver failure Caused by 'fat burners' and dietary supplements: a case report and literature review. In: Canadian journal of gastroenterology = Journal canadien de gastroenterologie. Volume 25, Number 3, March 2011, pp. 157-160, ISSN  0835-7900 . PMID 21499580 . PMC 3076034 (free full text).
  7. ↑ LM Hsu, YS Huang, FY Chang, SD Lee: "Fat burner" herb, usnic acid, induced acute hepatitis in a family. In: Journal of Gastroenterology and Hepatology . Volume 20, Number 7, July 2005, pp. 1138-1139, ISSN  0815-9319 . doi : 10.1111 / j.1440-1746.2005.03855.x . PMID 15955234 .
  8. ^ R. Jantos, KM Stein, C. Flechtenmacher, G. Skopp: A fatal case involving a caffeine-containing fat burner. In: Drug Testing and Analysis . Volume 5, Number 9-10, 2013 Sep-Oct, pp 773-776, ISSN  1942-7611 . doi : 10.1002 / dta.1485 . PMID 23661579 .

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