As I've said before, losing weight is hard work. Most educated adults know by now that they have to make some pretty radical changes in their diet and exercise routine, and sustain them, in order to reach their goals, but that doesn't necessarily stop them from looking for those supplements that might help them lose those last 5 or more pounds. And one of those supplements that has recently come up again, thanks to Master of Woo Dr. Mehmet Oz, is conjugated linoleic acid, or CLA.
I say "come up again," as this was popular in the late 1990s when I first started practicing (and I'm feeling a little old). But can taking this as a supplement really help us achieve our lose fat/build muscle goals?
CLA is actually a type of omega-6 fatty acid, one of those essential fats that our body needs to obtain from the diet as we cannot make it on our own. It is also a type of trans fat, which immediately scares some people because they know that the trans fats found in margarine, etc are associated with inflammation, insulin resistance, etc. Fortunately, these type of naturally occurring trans fats acutally have the double bond in a different place (better living through chemistry), and have being showing some promise as far as inhibiting tumor growth/certain kinds of cancers at least if you are a rat (in other words, this might benefit humans, or it might not, depending on what future research shows). The best sources of this type of fat is from the meat and milk of grass fed ruminant animals (cows, sheep, deer, etc), and second best would be the milk and meat of silage fed ruminants, as well as eggs from chickens fed CLA. Vegans sources of CLA would be safflower oil and common/white mushrooms.
That's all well and good, but when it comes to losing weight, the amount of CLA recommended is well over what most people would get from eating food. This should raise a red flag, as there is already signs of a "more is better" philosophy that we are so fond of in the United States (usually to our detriment), and the studies are conflicting. There are some studies that indicate that this supplement might help people lose weight--to the tune of a person losing an average of one pound of fat over an average of 5 weeks (Link), and that doesn't sound very promising to me. Other studies indicated that there was no net loss of body fat at all. Even more troubling was indicators of increased insulin resistance in some overweight individuals, increasing the risk of developing diabetes and altering cholesterol levels in a non-favorable way, although the studies are conflicting here as well (Link).
And then of course there is the price. When I looked on Amazon.com you are usually going to pay about 10-15 cents per capsule (which is cheaper than what Dr. Oz sells on his website), so you will average about $10-14 per month. If it were me, I could think of other ways to spend that money for something that is probably not going to help me lose much fat, and might even be harmful given that I have a strong family history of insulin resistance already.
Take home message--consuming conjugated linoleic acid from naturally occuring food sources does not seem to be a problem, and might even be beneficial for protecting against certain cancers (take caution). Using it as a weight loss supplement might cause problems for those already at risk for diabetes, cardiovascular disease, and spending money on things you don't need.