On a Christmas ski trip, I was thumbing through the airline magazine when I spotted an ad by a “plastic surgeon to the Hollywood stars” touting a miraculous, safe belly fat loss pill. The surgeon was now recommending this supplement in lieu of liposuction! Although not mentioned by name, I realized this “scientific breakthrough” was conjugated linoleic acid (CLA), which has been known for 20 years.

CLA is a mixture of cis- and trans-isomers of the 18-carbon fatty acid linoleic acid. These isomers have adjacent (conjugated) double bonds, so they cannot replace the essential cis-linoleic acid. CLA products are typically 40%:40% cis-9,trans-11 and trans-10,cis-12 isomers, with the remaining 20% variable. The CLA cis-9,trans-11 isomer is found naturally in meat and dairy products.

Fed in large doses to obese mice on controlled diets, CLA significantly reduces abdominal fat in 12 weeks without wasting muscle. It is the synthetic trans-10,cis-12 isomer, not the natural cis-9, trans-11 that appears effective. However mice live only 2 years; a human lifespan is 30-40 times longer. Twelve weeks becomes 480 weeks—many years. The good news about CLA is that we actually have recent controlled human studies on this supplement. The bad news is that if diet and exercise don’t change, it could be 12 months, 24 months, or never before a human sees a 2 to 4 pound waistline reduction from taking eight CLA capsules per day. Just skipping 400 calories daily would be much faster and cheaper.

Older people do suffer from altered/reduced metabolisms that cause central obesity coupled with reduced muscle and bone mass in the shoulders, arms and legs. Even those who don’t appear “fat” are often skinny, not lean. While preferable to obese, skinny means you don’t have too much body fat. However, it also means you do you have much muscle (or bone). Skinny does not protect you from Type II diabetes, cardiovascular disease, arthritis, or catastrophic falls. Lean—possessing a healthy complement of bone and muscle without excess body fat—however is highly protective against metabolic and inflammatory diseases and injury. 

Should our industry recommend CLA to older people? Many of them cannot utilize stimulant (amphetamine-like) weight reduction supplements/drugs due to the risks of hypertension, stroke, and cardiac arrhythmia; further stimulants indiscriminately waste precious muscle. I would recommend 3g fish oil (or vegan DHA equivalent) 3g CLA, magnesium, vitamin C, and strength training. Using CLA alone is disingenuous at best.