Conjugated linoleic acid, also known as CLA, is a naturally-occuring fatty acid that’s found in dairy and meat. CLA is popular among athletes, bodybuilders, and regular people looking to lose weight. Research suggests that CLA could help you cut body fat while maintaining lean body mass, which makes it a great compliment to a weight loss program.
Don’t make the mistake of thinking that CLA is just a quick-fix weight loss supplement, though. The fatty acids in conjugated linoleic acid are one of the primary sources of the heart health benefits of dairy, and CLA supplements can also boost indicators of cardiovascular health, potentially reducing your risk of heart disease.
Check out these surprising benefits to conjugated linoleic acid:
1. CLA is found naturally in beef and dairy
Conjugated linoleic acid (CLA) is a fatty acid naturally occurring in dairy products and beef that has powerful positive health benefits. (1)
Among the most popular weight loss supplements used worldwide, CLA may also reduce the risk of developing type 2 diabetes and cancer. (2, 3, 4)
Large amounts of linoleic acid can be found in vegetable oils, and smaller amounts are found in other foods. Linoleic acid is a polyunsaturated fatty acid, and the most common of the omega-6 fatty acids.
But CLA has a different molecular structure: “conjugated” refers to the way the double bonds are arranged. For those of us who aren’t chemists, understanding how molecular bonds affect the way our bodies react to a substance can be a tough call, but just like with words, colors and facial features, arrangement is everything.
2. CLA is different in structure than unhealthy trans fat
The placement of one of these types of bonds is structured in a way that classifies CLA as a trans fat, although it’s natural, and therefore not dangerous like industrially created trans fats that can cause damage in our bodies. (5, 6, 7)
Dietary CLA comes from the meat and dairy products of ruminant animals such as cattle, sheep and goats. The amount of CLA contained in these foods depends entirely on what the animals consumed. (8)
Keep in mind that the majority of animals meeting modern commercial demand for these foods are born and raised in industrial settings, eating mostly grains and soy products. In contrast, dairy animals of past times grazed and foraged, eating what they could find in their environment, including dried grasses and small amounts of grain during cold seasons.
3. CLA is found in much higher amounts in grass-fed meat
The CLA content of products from grass-fed cows, including the meat after butchering, delivers between 300% and 500% more CLA than products from animals eating grains (9). The high CLA content of grass-fed meat is one of the primary reasons grass-fed meats are thought to be healthier than factory-farmed meat.
While you can also get CLA in regular (i.e. grain-fed) beef, the fat profile is better for grass fed beef, and the CLA content is higher, so it is overall a better and healthier option.
4. Research suggests that CLA may help support weight loss
Animal studies have found that CLA can reduce calorie consumption, increase calorie burning, boost fat oxidation, and inhibit the production of fat cells. (10, 11, 12, 13)
Subsequent human studies indicate CLA may have anti-obesity properties in humans as well. (14, 15)
Controlled randomized trials on the effects of CLA on weight loss show mixed results. Some indicate CLA can play a role in modifying body composition, reducing fat mass and sometimes even increasing muscle mass (16, 17, 18).
When researchers correlated data from 18 controlled trials, the results for participants added up to between anywhere between .02 and 3 pounds weight loss per week over a six-month period (19).
Observational studies can’t deliver the same level of evidence-based proof than randomized, controlled trials because of variable factors; that being noted, a number of observational studies indicate people who eat foods containing high levels of natural CLA may enjoy a reduced risk of developing chronic diseases.
5. CLA works well in conjunction with a healthy diet and an exercise program
CLA works best for people who are working on dropping body fat, especially if they’re already eating reasonably well and getting exercise—both of which also help with CLA’s primary health effects, which are dropping body fat, boosting immunity, and lowering blood lipids. If these are your goals, CLA is a great supplement.
6. Higher CLA intake is associated with lower rates of diabetes and cancer
Type 2 diabetes appears to develop less frequently when the diet is rich in CLA, as well as a lower incidence of cancer. (20, 21, 22)
People living in countries where cows are grass-fed have higher levels of CLA in their bodies; observational studies confirm their chances of suffering from heart disease are significantly lower (23).
Whether or not the difference in the incidence of chronic disease is due to adequate levels of CLA has not been established.
Grass-fed animal products are also rich in other nutrients with proven health benefits, such as vitamin K2, which affects the distribution of calcium in the body and may prevent heart disease by protecting the arteries.
Evidence shows naturally-occurring CLA can provide health benefits ranging from supporting weight control to protecting against the development of chronic disease.
CLA side effects
CLA is quite safe, especially among weight loss supplements, which is why it’s widely regarded as one of the best natural supplements for weight loss, beating out better-known compounds like raspberry ketones or caffeine. CLA is an easy addition to your supplementation routine, and helps both short-term and long term health goals.
A few studies have reported diarrhea, nausea, and mild gastrointestinal disturbances like gas and bloating (24,25); aside from this, many other clinical trials have reported no negative side effects associated with CLA.
A number of participants in the studies cited above experienced mild side effects including stomach pain, flatulence, diarrhea and nausea (26). The chances you’ll experience similar side effects are higher when you take more CLA.
The fact that CLA can cause some mild gastrointestinal symptoms should not be surprising, since large doses of pretty much any fatty acid (like MCT oil) can cause stomach issues. Taking CLA at a moderate dosage, and splitting this dose up into two or three separate doses taken throughout the day, may be able to help with side effects.
CLA recommended dosage
A lot of the research that’s been done on CLA has been in animal models, which make it difficult to extrapolate dosage information to humans. As such, the most reasonable estimates of appropriate CLA dosage have to come from human studies.
These human studies have used dosages ranging from below one gram per day to up to six grams per day. This is far higher than the CLA intake that a typical person gets from their diet which is about 150 mg for women and 200 mg for men (27).
Several studies that found positive benefits to using CLA tended to use dosages of between three and six grams per day, which is a good place to start.
For reference, a typical CLA supplement might contain between 1.0 and 1.3 grams of CLA per capsule; for reference, one serving of grass-fed beef (the best natural source of CLA) might have about 0.5 grams of CLA. Dairy products tend to have lower levels of CLA; even consuming butter, you only get about .1 grams per serving tops (28, 29).
CLA benefits FAQ
Q: What foods have CLA in them?
A: Foods that are rich in CLA include dairy products and various kinds of meat. However, there are some specific types of these foods that are higher in CLA than others. For dairy products, you should look for full-fat products like butter, whole milk, and cheese; for meat, you should look for grass-fed animals, particularly grass-fed beef.
Grass-fed sources are better than grain-fed sources, because the CLA content is higher in grass-fed versus grain fed animals. Grass-fed animal foods have the additional advantage of having lower overall levels of fat, but higher relative amounts of CLA, according to a study published in 2010 in the Nutrition Journal (30).
If you can’t get enough CLA in your diet to meet your nutrition goals, you can always turn to a CLA supplement for an easy way to up your CLA intake.
Q: Can CLA give you diarrhea?
A: Diarrhea is one of the potential side effects that has been identified in clinical studies of CLA supplementation. Two randomized controlled trials reported nausea and diarrhea in a few subjects who took CLA, but in one, the actual rate of side effects was no lower in the people in the placebo group (31,32).
More generally, gastrointestinal side effects like diarrhea are known to occur when excessive doses of specific fatty acids are taken supplementally—the best example of this is probably MCT oil.
Keeping your CLA dosage in the recommended range of three to six grams per day is the best way to avoid diarrhea. You can also split your doses up into several smaller doses to take throughout the day.
Q: How much weight can you lose from CLA?
A: According to a study that pooled the results of several different clinical trials of CLA’s weight loss benefits, you can expect CLA to boost your weight loss by around 0.2 pounds per week, when taken at a typical dose of 3.2 grams per day.
This magnitude is small enough that some nutritionists question whether it’s clinically relevant, but if you stack the benefits of CLA on top of the benefits of other weight loss interventions (like diet and exercise), the amount of weight you can lose starts to add up.
The relatively modest effect size of CLA on weight loss likely explains why it is also popular among bodybuilders: they aren’t usually looking to cut huge amounts of weight; rather, their goal is to drop body fat while maintaining muscle mass, which CLA is well-suited for. CLA is a great way to tilt the scales in your favor, towards more fat burned and more muscle mass retained.
Q: Should you take CLA before bed?
A: The primary hypothesis for CLA’s mechanism of action is that it inhibits biochemical pathways that fat cells use to synthesize and store fat (33).
Based on this mechanism, it is probably better to have high CLA levels in your body all day, rather than taking it before bed specifically.
No research in humans has specifically compared taking CLA before bed to CLA at any other time during the day, so feel free to take your CLA supplement whenever is convenient for you.
Q: Is CLA vegan?
A: Naturally-occuring CLA is typically not vegan, and the only vegetarian sources of CLA (dairy products) are lower in CLA than grass-fed meat, which is the best way to get a lot of CLA as part of your diet.
However, some of the top CLA supplements use safflower oil as their source of CLA, and provide the supplement in a cellulose-based capsule, which make them totally vegan-friendly. If you want the health benefits of CLA without incorporating animal products into your diet, a CLA supplement is the way to go.
Related: Our top CLA supplement picks
Conjugated linoleic acid is a simple, naturally-occurring compound that may help you lose weight and improve your cardiovascular health.
It’s found in high amounts in grass-fed beef and in moderate amounts in dairy, so incorporating more of these healthy foods is a great way to boost your CLA intake.
If you want to get the same level of CLA intake as has been used in research studies on CLA for weight loss, you’ll want a high-quality CLA supplement. Aim for three to six grams of CLA per day if you are taking it as a supplement.
If you’re looking for a simple and all-natural supplement to boost your fat burning and improve heart health, CLA is a great choice.