Some of our best dietary intentions are often completely derailed by an insatiable hunger. Some dietary modifications, such as increasing protein intake, can possibly increase satiety (1). More methods of reducing the common hunger pains are continuously being researched. Some researchers suggest that you should swap vegetable oil with coconut oil or with natural trans-fat in order to keep your appetite suppressed and possibly also support your weight loss goals. But aren't trans fats undeniably unhealthy? Yes - fast-foods contain synthetically-made trans-fats which are detrimental to health, but CLA (conjugated linoleic acid) is produced naturally in the digestive tract of buffalo, goat and cattle. Research on the health benefits and potential weight loss support of CLA, however, is still conflicting. It can possibly reduce food intake and increase satiety and is, therefore, worth taking a look at.
More About CLA
CLA can be naturally found in dairy products and meat, vegetable oils (in small amounts) and animal fats such as eggs, whole milk, lamb and beef. It is related to omega-6 fatty acids (an essential fatty-acid that keeps cholesterol levels in check (2), boosts the immune system and increases metabolic rates).
Even though CLA cannot be produced by the human body, it offers a variety of potential health benefits such as reducing body fat, increasing satiety (3), preventing cancer (4) and heart disease. Even though, as already mentioned, synthetically-made trans-fats are definitely harmful to health, CLA is produced naturally in the digestive tracts of some animals and is, therefore, much less harmful to health.
Animals such as giraffes, buffalo, bison, moose, goats, deer and cows have four different compartments in their stomach; rumen, reticulum, omasum and abomasum. These types of animals are called ruminants (or even four stomach animals) and consist of around 150 species in total. How the food is digested is where the difference comes in between a ruminant and a human. The food is turned into cud with rumens, which is disgorged, re-chewed and swallowed again - CLA is created from this process.
When the linoleic acid or omega 6 fatty acids in the digestive tract are fermented by bacteria, some gets turned into the conjugated form. The food of four-stomach animals gets fermented extensively which leads to a much higher concentration of CLA. Foods derived from these types of animals are the very best sources of CLA.
CLA is naturally produced in the digestive tracts of animals such as cows, buffalo and giraffes. Typical food sources are, therefore, beef and dairy products. CLA offers a variety of health benefits such as boosting the immune system, preventing cancer and increasing satiety.
What Do The Studies Show?
A study was done on a group of people who consumed a breakfast with different fat contents, containing either vegetable oil, MCT (medium-chain triglycerides) oil or vegetable oil and CLA (5). The participants were served a lunch (buffet-style) on request. Energy intake was measured at lunch as well as for the rest of the day. Satiety and the time between lunch and breakfast were also recorded. The CLA and MCT breakfast led to more time before lunch was requested and it also led to fewer calories being consumed throughout the day when compared to the breakfast served with vegetable oil only.
The results of this study, therefore, shows that substituting CLA or MCT for vegetable oil at breakfast can reduce food intake substantially (by as much as 500 calories per day). This can add up to a lot of pounds lost over time.
Other studies have found that CLA may increase fat breakdown, while also using more fat to fuel muscles (6). It has yet to be confirmed, however, whether CLA's glycogen-sparing effect serves as a satiety signal.
Studies show that when CLA is taken with breakfast, it led to a longer period of time before lunch was requested as well as to participants consuming up to 500 fewer calories throughout the day.
CLA Diet/Supplement For Weight Loss
The way in which CLA can possibly reduce body fat is based on the following two theories of action:
- The inhibition of a specific enzyme (lipoprotein lipase) reduces lipid uptake into fat cells.
- The accumulation of triacylglycerol (a blood lipid which enables the transfer of glucose and fat from the liver) is reduced in fat cells.
It is important to note that even though CLA may assist with a decrease in body fat percentage, weight might not necessarily be decreased as it will also assist with increasing lean muscle mass (7).
An increase in muscle mass does, however, mean that the body burns more calories at rest (as muscles are metabolically active). This means that the more muscles you have, the more energy you will need even when resting.
Remember that even though building muscle might boost your confidence, it takes consistency and time. The key is maintaining a healthy diet and exercising regularly. Find out more about how to build muscle (8).
CLA reduces body fat by reducing lipid uptake into cells. It does not only reduce body fat percentage but also increases lean muscle mass. This will lead to the body burning more calories while resting.
How Does It Work And Who Can Benefit?
CLA can increase basal metabolic rates and, therefore, reduce body fat. It helps the body to convert food into energy more efficiently. 3.4 grams of CLA should be taken daily in order to receive benefits and it can be taken before or with meals. Keep in mind that it is definitely not a magic drug and that it will not make up for lack of exercise or poor eating habits. It should rather be seen as a supplement that should be taken while pursuing a healthier lifestyle. Rather see it as a tool which might make it easier for people to stick to their diets. Read more about the implication of CLA in human health (9).
Other possible health benefits of CLA, are the following:
- The body can easily become more susceptible to illnesses and being run down when exercising and dieting regularly. CLA might help to boost the immune system as it prevents tissue breakdown of the immune system while you are ill.
- Increased oxygen consumption.
- Increased energy expenditure.
- Acts as an antioxidant.
- People who have a diet high in CLA are at a lower risk of diseases such as cancer and type 2 diabetes (10).
- People who live in countries where they mostly eat grass-fed beef rather than grain-fed beef, also have a lower risk of heart disease. This might also be because of other protective compounds in grass-fed animals, such as vitamin K2. Grass-fed dairy products and beef are also healthy for various other reasons.
CLA is not a magic drug and should be taken in combination with a healthy lifestyle in order to receive the most benefits. Other health benefits associated with CLA use is a better functioning immune function, lower risk of type 2 diabetes, cancer and heart disease.
CLA Diet Food Sources
There are luckily many natural sources of CLA and the items are generally not exotic and expensive foods. Unfortunately, even the best sources contain tiny amounts, making it challenging to get your daily dose solely from food sources.
If you prefer to get your daily CLA dose only from food, there are many sources to choose from. Pork and chicken contain small amounts of CLA, while veal, lamb and turkey contain significantly higher amounts. If you are not a meat-lover, there are also a few vegetarian-friendly options which include most dairy products such as Colby and Swiss cheeses, cottage cheese, butter, sour cream, yogurt and homogenized milk. Vegans can get their dose of CLA from pomegranate seed oil, sunflower oil, safflower oil and white button mushrooms. Here is a list of how much CLA you'll ingest when having your favorite foods:
- A 4 oz serving of grass-fed beef - 433 mg of CLA
- Grass-fed whole milk - 240 mg
- 1 oz of cheese from grass-fed cow milk - 20-30 mg of CLA per gram of fat
- 8 oz buttermilk - 5.4 mg of CLA per gram of fat
- 1 oz processed cheese - 5 mg of CLA per gram of fat
- 6 oz container plain yogurt - 4.8 mg of CLA per gram of fat
- 1 tablespoon butter - 4.7 mg of CLA per gram of fat
- 1 tablespoon sour cream - 4.6 mg of CLA per gram of fat
- 4 oz cottage cheese - 4.5 mg of CLA per gram of fat
- 6 oz container low-fat yogurt - 4.4 mg of CLA per gram of fat
- 1 oz cheddar cheese - 4.1 mg of CLA per gram of fat
- 8 oz 2% milk - 4.1 mg of CLA per gram of fat
- ½ cup of ice cream - 3.6 mg of CLA per gram of fat
- 4 oz veal - 2.7 mg of CLA per gram of fat
- 4 oz fresh ground turkey - 2.6 mg of CLA per gram of fat
- 4 oz chicken - 0.9 mg of CLA per gram of fat
- 1 tablespoon safflower oil - 0.7 mg of CLA per gram of fat
- 1 large egg yolk - 0.6 mg of CLA per gram of fat
- 4 oz pork - 0.6 mg of CLA per gram of fat
- 1 tablespoon of sunflower oil - 0.4 mg of CLA per gram of fat
- 3 oz salmon - 0.3 mg of CLA per gram of fat
- 1 tablespoon of coconut oil - 0.1 mg of CLA per gram of fat
It is important to note the high amount of CLA contained in grass-fed beef and milk/cheese coming from grass-fed cows compared to grain fed animals. Grass-fed products contain 500% more conjugated that grain fed cows. Those animals eating grass consume higher amounts of omega-6 fatty acids and are, therefore, producing much higher amounts of CLA, a contrast to the factory cow which eats unnatural food and corn.
Beef, dairy, safflower oil and white button mushrooms are some of the food sources that contain CLA. When consuming meat and dairy products, it is important to choose grass-fed products as they contain 500% more CLA than grain-fed products.
Is A CLA Diet Good For My Health?
Many foods that contain CLA contains harmful fat (especially saturated fats). This might be detrimental to your health as saturated fat often correlates with an increased risk of heart disease. These foods should, therefore, be eaten in moderation and it might, for that reason, be difficult to keep a balanced diet while boosting your intake of CLA. Read more about the effects on body composition and the safety of the long-term use of CLA supplementation in humans.
Foods that contain CLA often contain saturated fats and might, therefore, be harmful to your health. It should rather be eaten in moderation if you're trying to follow a well-balanced diet.
CLA Dietary Supplements
Supplements are probably the best bet if you are interested in the health benefits of CLA as the highest sources of CLA in foods are also very fattening. As these sources are often really calorie-dense, it might be quite disastrous to your diet.
To get the same amount of CLA as a 1000 mg CLA capsule, you would need to eat the following:
- 9.25 oz of grass-fed beef
- More than 6 cups of milk from grass-fed cows
- More than 22 cups of whole milk
- 1.5 lbs of cheese
- 19 cups of ice cream
These calculations are only for a single 1000 mg capsule, while 3000 - 8000 mg of CLA is recommended for losing belly fat and for weight loss support. That means that you would have to eat at least three times the amounts mentioned above in order to start seeing weight loss benefits - which might not be the case at all if you take all the calories that would need to be consumed into account.
It is almost impossible to get the same amount of CLA included in a single 1000 mg supplement from your food - as the number of calories that would need to be consumed would be way too much.
What Are The Side Effects?
Even though small amounts of CLA from both food and supplementation can be beneficial, it is important to keep in mind that some nutrients and molecules may become harmful when taken in large amounts. Even though it would be difficult to get a high enough dosage of CLA solely from the food you eat, you should remember that the CLA found in supplements is made from vegetable oils from which the linoleic acid is chemically altered. This is a different form of CLA than found in food sources such as beef or dairy.
High doses of CLA can cause an increased accumulation of fat in your liver and this might be a stepping stone towards certain diseases such as metabolic syndrome (13). Studies further show that it can lower HDL (good) cholesterol, cause insulin resistance and drive inflammation (14). Keep in mind that these studies used much higher doses than people typically get from supplements. However, reasonable doses may cause mild side effects such as oxidative stress and diarrhea.
There are a few serious side effects associated with ingesting really high doses of CLA, such as insulin resistance, increased inflammation and metabolic syndrome. Mild side effects, such as diarrhea and oxidative stress can be experienced with reasonable doses.
How Much Should I Take?
At least 3 grams per day is necessary for weight loss. Up to 6 grams taken per day is still considered safe with no serious side effects reported. The FDA gives CLA a GRAS status (generally regarded as safe) and they do allow that CLA may be added to food. Keep in mind that the risk of side effects might increase as your dosage increases.