Its a question that we often see crop up but rarely correctly answers. What does science tell us?
Many supplement shelves and companies will tell you it has great fat burning potential. Is this true?
Its all a lie!
The weight of current scientific evidence suggests no!
Why do you say this?
Having a dig into the Conjugated linoleic acids (CLA) study archives the following data we thought was most pertinent.
In the study Conjugated linoleic acid intake in humans: a systematic review focusing on its effect on body composition, glucose, and lipid metabolism (2006) the following conclusion was drawn “After analyzing the few studies published to date in reduced samples of healthy humans or patients with overweight, obesity, metabolic syndrome, or diabetes, we deduce that there is not enough evidence to show that conjugated linoleic acid has an effect on weight and body composition in humans.”
It then actually went onto say that “some of these studies have observed that the administration of various CLA isomers has adverse effects on lipid profile (it decreases HDL cholesterol concentration and increases Lp(a) circulating levels), glucose metabolism (glycemia, insulinemia or insulin sensitivity), lipid oxidation, inflammation, or endothelial function.” which is a very negative result to have drawn.
In another study The effects of conjugated linoleic acid on human health-related outcomes (2005) again they stated “The consensus from seventeen published studies in human subjects is that CLA does not affect body weight or body composition. Some detrimental effects of the trans-10,cis-12 CLA isomer have also been reported in terms of altered blood lipid composition and impaired insulin sensitivity.” Once again no positive outcome was registered with body composition and again lipid and insulin sensitivity issues were noted- not good!
In the final study we looked into (Effects of conjugated linoleic acid supplementation during resistance training on body composition, bone density, strength, and selected hematological markers, 2002) we found that they reported “CLA supplementation did not significantly affect (p > 0.05) changes in total body mass, fat-free mass, fat mass, percent body fat, bone mass, strength, serum substrates, or general markers of catabolism and immunity during training. These findings indicate that CLA does not appear to possess significant ergogenic value for experienced resistance-trained athletes.” Once again showing that CLA had no benefit for the avid bodybuilder.
In short, we see no reason to recommend using CLA and several relating to lipid levels and indeed insulin sensitivity all heading in a negative direction.
In short? There is many reasons not to use CLA and no reason we can see for recommending it.
Studies can be seen here:
Conjugated linoleic acid intake in humans: a systematic review focusing on its effect on body composition, glucose, and lipid metabolism – https://www.ncbi.nlm.nih.gov/pubmed/16864141
The effects of conjugated linoleic acid on human health-related outcomes – https://www.ncbi.nlm.nih.gov/pubmed/15960862
Effects of conjugated linoleic acid supplementation during resistance training on body composition, bone density, strength, and selected hematological markers – https://www.ncbi.nlm.nih.gov/pubmed/12173945