Of the products that are readily available claiming to increase fat burning and improve weight loss both caffeine and carnitine are probably the most touted. You also find these two in the ingredients list of most fat burners. The question really is “do they work and where is the evidence”?
Caffeine and Weight Loss
Many things are claimed for caffeine and it is certainly one of the most researched drugs available to the public. I say drug because it is a pharmacological agent as it acts as a stimulant. Now at this point I could go into the three molecules that make up caffeine and each of their biochemical actions. For the purpose of this article that would be a waste of your time and you’d be none the wiser. The simple fact of the matter is that because it is a drug your body becomes sensitised to its effects very quickly. If you are regular coffee or tea consumer or drink a few sports drinks there is a fair chance that you are already fairly desensitised to the effects of caffeine. Because of this the chances of caffeine having any major effect on your body and in particular weight loss are diminished. The actual pharmacological action of caffeine is primarily on the central nervous system and not directly on adipose tissue (fat cells) as was once believed. The other thing to bear in mind is the dosage required to get a physiological response. Current evidence suggests that this is in a range between 3mg to 9mg per Kg bodyweight, and this is most effective if you are caffeine naïve (don’t consume any caffeine in daily life). When you work out how much you need to consume to get an effect it is actually quite a lot and most people don’t respond at the lower end of this dosage. So the bottom line is that caffeine is not an effective aid for fat burning or weight loss, the current scientific evidence does not support these claims.
Carnitine and Weight Loss
Carnitine is found in many forms in many products claiming to enhance fat burning. In terms of biochemistry this is where it works (you can skip this bit if you like): The uptake of fatty acids in to the cell and their subsequent translocation across the mitochondrial membrane is facilitated by carnitine. In the cytoplasm fatty acyl-coenzyme A (acyl-CoA) combines with carnitine and this permits fatty acids to move into the mitochondria. So it is true to state that carnitine is involved with fatty acids. Without going into this in further detail it is pretty easy to discard carnitine as a fat burner as it has been studied extensively. Research has shown that carnitine deficiency is not a problem for athletes or the general public. Red meat and dairy products are good sources of carnitine and we also produce it in the body by synthesising lysine and methionine in the liver and kidneys; so it is not an issue for vegetarians. Most studies that have investigated the effects of carnitine supplementation on carnitine concentrations in the muscle have found no effect either on the muscle concentrations or on fat oxidation/weight loss. The ACSM position stand on nutrition and athletic performance lists carnitine as an ergogenic aid that does not perform as claimed.
These are both very good examples of marketing hype and anecdotal evidence winning out over the cold hard facts. Let’s face it, if either worked then every overweight person would be taking them and we wouldn’t have an obesity epidemic. Well just look around you to figure out the truth, we definitely have an obesity epidemic? If you want further nutritional hints and tips why not sign up for my FREE seven video series. Just complete the simple form below to start receiving them straightaway.