To answer your question, let me first give a little background on CLA. For those who don’t know, CLA stands for conjugated linoleic acid. Simply stated, CLA is a derivative of the omega-6 compound, linoleic acid. In more technical terms, CLA is an isomer of linoleic acid, meaning there is a slight rearrangement of its molecular structure (this accounts for the “conjugated” moniker). In nature, CLA is found primarily in meats and dairy products, but the amounts in these foods are relatively low and most people therefore get very little in their diet.
Numerous animal studies (mostly on rodents) have shown that CLA supplement helps expedite fat loss. Interestingly, these studies have generally revealed little or no change in bodyweight. Rather, there is a profound change in the animals’ body composition, with more muscle and less fat – a very encouraging finding in favor of CLA supplementation. Although its exact mode of action isn’t clear, CLA seems to rev up fat-burning enzymes and/or decrease activity of fat storage enzymes in rats and mice, thereby promoting a leaner, stronger animal.
Unfortunately, studies on humans have been less than exciting. Although lipid profiles seem to improve somewhat with CLA supplementation, most people derive little or no benefit from CLA from a body composition perspective. Why the differences between animals and humans? Realize that the metabolism of rodents is approximately seven times greater than that of humans, meaning their results from a fat burner would be magnified by about sevenfold. (There are other fundamental differences in physiologic makeup that also could account for variations in response).
That said, there have been a few studies suggesting CLA does have benefit for those who are obese. It’s theorized that obese people might overexpress a certain gene called PPAR-gamma and that CLA somehow helps to neutralize this gene, thereby aiding in fat loss. Lean people, on the other hand, don’t have this problem and thus, don’t see much in the way of results.
Bottom line, CLA has limited utility for those trying to lose those last few pounds. Given its relatively high cost, the potential benefit probably doesn’t justify the expense. On a positive note, however, there are some new isomers of CLA being developed that could possibly be more effective than what is now on the market. Stay tuned …