After the tips included here: Original V-Diet Plan by @Chris_Shugart my interest in CLA returned. As a result of my quick reading, I’m not sure what precisely to believe, short of reading more and continuing to take CLA in the interim.
I meant the below response for Chris in that thread, but decided to make a new one.
I’ve been on the CLA train for a while, but hadn’t done any reading recently, which just lead me to a few articles with citations of their own. I have not read the sources of the two below, but noted that the more recent article did not mention any which were mentioned in the older article. The one positive study from the nutrientjournal.com article was noted as partially sponsored by CLA producers (quote below):
1 Published, 2016 [CLA unreliably affects lean mass and fat mass; no hormonal interaction](http://nutrientjournal.com/cla-unreliably-affects-lean-mass-fat-mass-no-hormonal-interaction/)
Subjects were randomly assigned to three groups: CCP (6 g/day CLA, 9 g/day creatine, 36 g/day whey protein), CP (9 g/day creatine, 36 g/day whey protein, 6 g/day placebo), or P (45 g/day whey protein, 6 g/day placebo) during 5 weeks of strength training.
Analyses showed bench-press and leg-press strength increased more in the CCP group than in the CP + P groups combined (p < .05). Study also reported that group ingesting conjugated linoleic acid, creatine and protein increased lean tissue mass more than the other two groups combined. Creatine and protein group increased lean body mass significantly (p < 0.05) more than protein only group. Study therefore concluded that CLA supplementation during strength training might have more of an effect than creatine and protein on measures of strength . The study was partially sponsored by a company that produces CLA.
CLA tested in vitro (Leydig cells) increased the synthesis of testosterone via unknown mechanism . However, when same researchers tested CLA in human subjects (6g of CLA daily for 3 weeks) testosterone remained unchanged compared to placebo. Furthermore, CLA also didn’t affect estradiol, cortisol, and SHBG blood levels either before or after a resistance exercise bout. CLA provided no anabolic relevance.
A popular belief among bodybuilders is also that CLA keeps cortisol at bay, however there is no scientific study to back this up.
There is also a concern that conjugated linoleic acid ingestion by extremely overweight people might cause aggravate insulin resistance , which may increase their risk of developing diabetes . In contrast to in vitro studies which observed anti-oxidative effects of CLA , studies in humans noted that especially trans -10 cis -12 (t10c12) CLA, is pro-oxidative .
2 Published, 2000 [CLA: Fat Loss And Muscle Gain: A number of studies have demonstrated that CLA reduces fat mass,while increasing lean body mass. Learn why research has proven this and which ones you should use.](https://www.bodybuilding.com/content/cla-fat-loss-and-muscle-gain.html)
CLA hardwires us to stay lean and clean, helping us to burn the calories that already exist, instead of craving additional calories that serve no purpose.
A recent study investigating the effect of 4.2 grams of CLA per day in 53 healthy individuals showed a significant decrease (3.8 percent) in body fat compared with individuals not taking CLA.
An additional study in obese and overweight populations demonstrated that at least 3.4 grams of CLA per day for a period of 12 weeks was actually necessary to see a significant reduction in body fat.2 In other words, without CLA intake there was no significant fat loss!