Supplement companies often hype up CLA for its supposed fat burning benefits, with many even going as far as to claim it can specifically target fat around the midsection.

Is this true?

This comprehensive article is going to find out, and it’ll also break down everything else you need to know about CLA supplementation. Let’s get stuck in!

What Is CLA?

CLA stands for conjugated linoleic acid.

It’s a dietary fat which is part of the Omega-6 family, and can be found in foods like milk and beef or, alternatively, you can supplement it (6-9g/day).

Supplement brands who sell CLA often say that it can shrink your waistline by preventing the body from storing fat. That’s because CLA can inhibit the enzyme lipoprotein lipase (LPL), which is responsible for your fat cells soaking up fat from your bloodstream, and encourage fat to be burned for fuel instead.

This would also mean it is great for muscle retention, too, because if you are using fat for fuel then your muscles are not being eaten up.

So in theory, this means CLA can prevent fat storage.

Conjugated Linoleic Acid: Russ’ Rating

Anyone who goes to the gym (i.e. 100% of people who read my website) will have just had their ears pricked up by the last section, right?

Sadly, things are not what they seem.

In some ways, the body of research surrounding CLA reminds me of Rocky V.

The movie starts off nicely (much like the research on CLA did when researchers were doing animal trials) but then Tommy Gunn is introduced (human trials) and the whole thing becomes a fucktacular shitnado of ass.

You see, all of the studies which show a positive fat burning element (i.e. the studies which supplement companies like to cite when trying to sell it to you) were animal trials. (1, 2)

Unfortunately, the results are nowhere near as good when we look at human trials.

Only two studies in humans have ever yielded positive results, and they were very questionable; one of them allowed participants to eat whatever they wanted and track their calories themselves (notoriously inaccurate), and the other did not instruct participants to track their calories AT ALL! (3, 4)

Studies where participants are placed on more tightly controlled regimens show no results at all.

A 2008 study in Obesity Journal found that continuous supplementation with CLA over a 12-week period led to zero fat loss versus placebo, and these results were doubled-down in 2011 when Canadian researchers replicated the findings in the Journal of Nutrition. (5, 6)

Heck there’s even one study where CLA supplementation caused weight GAIN! (7)

A 2012 meta-analysis considered to be the most comprehensive data on CLA supplementation to date showed that it has no effect on weight loss – and no effect on waist circumference – and even in trials where a few participants seem to respond well to CLA the results are very small indeed. (8, 9, 10)

As you can see, the body of research surrounding CLA is very sketchy indeed, and the majority of the hype surrounding its supposed fat burning effects seems to be coming only from supplement brands who are trying to sell it.

References:

1. Ostrowska E., et al. Conjugated linoleic acid decreases fat accretion in pigs: evaluation by dual-energy X-ray absorptiometry. Br J Nutr (2003).
2. Moya-Camarena S. Y., et al. Conjugated linoleic acid is a potent naturally occurring ligand and activator of PPARalpha. J Lipid Res (1999).
3. Watras A. C., et al. The role of conjugated linoleic acid in reducing body fat and preventing holiday weight gain. Int J Obes (Lond) (2007).
4. Chen S, et al. Effect of conjugated linoleic acid supplementation on weight loss and body fat composition in a Chinese population. Nutrition (2012).
5. Sneddon A. A., et al. Effect of a conjugated linoleic acid and omega-3 fatty acid mixture on body composition and adiponectin. Obesity (Silver Spring) (2008).
6. Joseph S. V., et al. Conjugated linoleic acid supplementation for 8 weeks does not affect body composition, lipid profile, or safety biomarkers in overweight, hyperlipidemic men. J Nutr (2011).
7. Riserus U., et al. Effects of cis-9,trans-11 conjugated linoleic acid supplementation on insulin sensitivity, lipid peroxidation, and proinflammatory markers in obese men. Am J Clin Nutr (2004).
8. Rahbar A. R., et al. Effect of Conjugated Linoleic Acid as a Supplement or Enrichment in Foods on Blood Glucose and Waist Circumference in Humans: A Metaanalysis. Endocr Metab Immune Disord Drug Targets (2017).
9. Onakpoya I. J., et al. The efficacy of long-term conjugated linoleic acid (CLA) supplementation on body composition in overweight and obese individuals: a systematic review and meta-analysis of randomized clinical trials. Eur J Nutr (2012).
10. Navarro V., et al. The body fat-lowering effect of conjugated linoleic acid: a comparison between animal and human studies. J Physiol Biochem (2006).