Conjugated Linoleic Acid for Weight Loss: Hope or Hype?

Every year or so, a new product arrives on the scene promising quick and easy weight loss. Our fantasy of a pain free solution to unwanted body fat is nothing new. In the 1970’s, I remember my groovy teenage babysitter sprinkling a “magic” weight loss powder (bought from the back of a fan magazine) on her macaroni and cheese.  It didn’t work. More recently, hydroxycitric acid, hoodia, and chromium picolinate have made their appearance. None are very effective, and all have the potential for side effects.

One of the hottest new supplements to grab popular attention is conjugated linoleic acid (CLA), a naturally occurring form of fatty acid found mostly in grass-fed cattle and other ruminant animals. According to the hypesters, CLA might shrink the size of fat cells, resulting in effortless weight loss. This sounds great, but can it really work?

To date, a number of scientific and pseudo-scientific studies have been published on CLA, but many were poorly conducted, or did not include adequate numbers of research subjects. To get to the heart of the matter, Igho Onakpoya and colleagues in the division of Complementary Medicine at the University of Exeter, in the U.K., painstakingly evaluated the available research.

After excluding studies that were simply inadequate, the researchers identified seven studies that met their criteria, accounting for a total of 974 participants. The data was carefully assessed and subjected to a rigorous statistical analysis. The upshot? CLA at a dose of 2.4 to 6 grams daily for at least six months netted an average weight loss of about 1.5 pounds, and an average body fat loss of about 3 pounds, although no overall change in waist size. Side effects, including diarrhea and stomach aches, were often reported.

At a cost of anywhere for $8 to $30 per month, it’s hard to justify taking CLA supplements, but that doesn’t mean that CLA isn’t good for you. Although we don’t know for sure, there may well be some health benefits to including CLA in the diet. Some evidence points to a lower risk for certain types of cancer in people whose diets include more CLA, including breast cancer, colon cancer, and prostate cancer. If you eat meat, you’ll get more than five times the CLA if you choose grass-fed over the more conventional feedlot-raised beef. Milk and other dairy products from these cattle are also higher in CLA. For vegans, mushrooms, including the ubiquitous white button mushrooms, are a reasonably good source of CLA.