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What's the Fuss about "Fat Burners" ?
You walk into a drugstore and you see rows upon rows of herbal remedies, fat burners, slimming teas, & other weight loss products. You open up a newspaper or magazine and advertisement are splashed across the page for the latest break-through pill which metabolises or binds fat! And you wonder if there is any truth in what these products are claiming and if you should try it. You are particularly tempted after the extra weight you gained over the festive season (which was a continuos celebration from Christmas to Valentine's & Easter). At least one of our readers did and asked the question "how effective are fat burner products & are there any side effects?"

Fat burner products contain a variety of ingredients ranging from fillers to fiber to what is claimed to be the key or active ingredient. I picked three of the most common ingredients found in these products to discuss.

Common Ingredients in "Fat Burners"
  • L-carnitine
    Function: L-Carnitine (or just carnitine) is an amino acid. It has a key role in the metabolism of fat; it transports fat into the cell to be oxidized or "burnt" to provide energy. Fat cannot penetrate the inner mitochondial membrane of the cell to be utilized unless it is paired to carnitine, thus carnitine has an important role in fat transport into cells.

    Claim: Supplement companies marketing fat burners products that contain carnitine claim that since carnitine is necessary for fat metabolism, taking extra carnitine will help you burn more fat, leading to weight loss.

    The Truth: Research has shown that extra carnitine does not enable more fat than usual to be burnt for energy. Even in athletes training hard, carnitine deficiency is rare. The body is very efficient in conserving carnitine, so taking more carnitine will not help burn more fat. Double-blind studies reveals that carnitine supplementation failed to get rid of the pudge. Subjects on low calorie diets undertaking exercise programs and supplementing with carnitine show no difference in fat or weight loss to those that did not use carnitine1,2,3.

    Side-Effects: From the studies that I found, L-carnitine has not been linked with any toxicity. Our body makes carnitine from lysine & methionine, in conjunction with vitamin C, iron, niacin, and vitamin B6.

  • Ephedra (Ma Huang)
    Function: Ephedra or Ma Huang has broncho-dilating and decongesting properties. The active ingredient, which is ephedrine, stimulate the central nervous system, dilate the bronchial tubes, elevate blood pressure, and increase heart rate. Pseudoephedrine (the synthetic form of ephedrine) is a popular over-the-counter remedy for relief of nasal congestion.

    Claim: Since ephedra is a central nervous system stimulant, it is believed that ephedra, particularly when combined with caffeine, promotes weight loss by increasing heart rate and possibly metabolism.

    The Truth: Many doctors discourage the use of ephedra as a weight-loss aid because of the many side effects that can occur with its use, especially since many of the side effects are intensified when ephedra is combined with caffeine.

    Side-Effects: Ephedra or Ma Huang has amphetamine-like side effects, including elevated blood pressure, rapid heart beat, nervousness, irritability, headache, urination disturbances, vomiting, muscle disturbances, insomnia, dry mouth, heart palpitations, and even death due to heart failure4. It interacts with drugs such as MAO-inhibiting antidepressants, digitoxin, or guanethidine, thus you should consult a physician before taking Ephedra or Ma Huang. FDA (Food and Drug Administration, USA) have determined that products contain the combination of Ma Huang and kola nut, a source of caffeine, can cause severe injury to people even under conditions of usual or recommended use. Reported reactions range from serious, life-threatening conditions such as irregular heartbeat, heart attack, stroke, seizures, hepatitis and psychosis, to relatively minor and temporary conditions such as dizziness, headache and gastrointestinal distress.

  • Chitosan
    Chitosan technically is not a "fat burner". It is touted more as a "fat trapper" or "fat absorber", but I have included it in this discussion as it has been in the news a lot & I've had many questions about it.

    Function: Chitosan is a derivative of chitin (pronounced KI-tin), a substance found in the shells of insects, crabs, lobsters, and other crustaceans.

    Claim: Sellers claim that chitosan causes weight loss by binding fats in the stomach and preventing them from being digested and absorbed. Some refer to it as a "fat magnet". It is added to diet pills because it is supposed to bind with fats in the digestive tract and filter them out before the body can absorb them.

    The Truth: A study involving thirty-four overweight volunteers in a randomized placebo- controlled double-blind trial where subjects were given four capsules of chitosan/placebo for 28 consecutive days. Results suggest that chitosan in the administered dosage, without dietary alterations, does not reduce body weight in overweight subjects5.

    Side-Effects: Since dietary fat is being excreted, you may have gastrointestinal side effects such as gas, bloating, diarrhea or fatty stools. More importantly, if chitosan really entraps a significant amount of fat, it would grab up all fats, including fat soluble vitamins and omega-3 fatty acids (a good fat), in trying to rid your body of the fats. Animal studies have show that chitin lowers vitamin E (a fat-soluble vitamin) levels in the body. It will also absorb medications that are encapsulated in fat-based compounds. These include some cholesterol-lowering drugs, as well as oral contraceptives and some forms of hormone-replacement therapy.
Buyer Beware
You can see from the above review that you have be vigilant regarding the supplements you may be considering. My best advice to you is not to take any supplement without first doing extensive research on it from scientific & reliable sources (not just reading literature from the manufacturers who have a vested interest in selling you their products) and speaking with your doctor. In addition, if you are taking any medication, you need to be extra sure that there are no interactions between the medication you are taking and the herbal supplement.
Product Labelling
A word of caution regarding what is labelled on the bottle and the actual content of herbal supplements. Herbal supplements is not a heavily regulated industry currently, although it is beginning to come under close scrutiny here in the US. Often what you would find is that there are discrepancies in what is on the bottle's label in terms of quantity & ingredients and the actual content. In one survey by the University of Arkansas for Medical Sciences, it was found that alkaloid content often differed considerably from label claims and was inconsistent between two lots of some products6. Sometimes, ingredients that are used as fillers are not labelled.
  1. Grunewald KK, Bailey RS. Commercially marketed supplements for bodybuilding athletes. Sports Med. 1993;15:90-103.

  2. Williams MH. Ergogenic and ergolytic substances. Med Sci Sports Exerc 1992:24; Suppl.: S344-8.

  3. Villanti RG, et al. L-carnitine supplementation combined with aerobic training does not promote weight loss in moderately obese women. Int J Sport Nutr Exerc Metab 2000;2:199-207.

  4. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative Medicine Communications, 1998, 1256.

  5. Pittler MH, Abbot NC, Harkness EF, Ernst E. Randomized, double-blind trial of chitosan for body weight reduction. Eur J Clin Nutr 1999 May;53(5):379-81.

  6. Gurley BJ, Gardner SF, Hubbard MA. Content versus label claims in ephedra-containing dietary supplements. Am J Health-Syst Pharm. 2000; 57:963-9.

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