The Skinny On Fats

In the 1980’s all fats were vilified.  Do you remember all the “fat-free” this and that commercials? The fat-free craze led to manufacturers replacing fat with sugars for palatability.  As a result, we have become more obese and insulin resistant than ever before.   In this article I will review how certain fats are not only essential to your health but are able to boost your performance in the gym.

We can’t live without fats and proteins.  There are “essential” fatty acids and amino acids that we can’t live without eating because our body can’t make them.  However, there are no such essential carbohydrates.  To suggest that we should live fat-free is an over simplification of the fact that we need to consume less calories no matter which way they come.  Since fats are calorie rich with 9kcal per gram vs. 4kcal per gram protein and carbohydrate, they are often limited first by dieters.  However, limiting sugar and carbohydrates should be the focus, while encouraging consumption of healthier essential fats.

In general, fats improve the digestion of your food.  Fats delay emptying of food from your stomach.  Fattier foods sit in your stomach longer and are better digested.  Additionally, by slowing the emptying of food from the stomach, sugars consumed in the meal reach your blood slower.  In doing so, fats effectively reduce the glycemic index of a meal.  Fats reduce the rapid rise in blood sugar that leads to insulin spikes to which your body becomes resistant as in type II diabetes.  Further, certain fats (LC-PUFAs; see below) have greater ability to reduce appetite than others1.

In addition to the digestive properties of fats, all fats are not created equal in their effects on your body.  Fats aren’t just a source of calories and insulation.  Fats are essential for the health of your nerves, your skin, your muscles, your brain, your heart and more.  Fats also make up the membranes of all of your cells and different fats have various effects on the fluidity of those membranes.  Your cells make inflammatory mediators like prostaglandins from the fats in your cell membranes; various fats forming various mediators.

Fats are made of a glycerol backbone and chains of “fatty acids”.  Fatty acids are energy rich carbon chains that have many hydrogen atoms attached.  When every carbon is full of hydrogen atoms a fat is considered “saturated”.  This is energy rich fat that solidifies at room temperature like lard.  The “unsaturated” fatty acids are oilier and have hydrogen’s missing at various locations which impart in the fatty acid different biological and physical properties.  When there are multiple carbon pairs missing hydrogen’s in a fatty acid (this forms a carbon to carbon double bond C=C) we call the fatty acid a polyunsaturated fatty acid (PUFA).  When the double bond (C=C) is at the third carbon atom from the end of the carbon chain the PUFA is called an Omega-3.  Similarly, there are omega-6 and 9’s with the last double bond at the 6th and 9th carbon from the end of the chain.  When the fatty acid only has one C=C it is called a mono-unsaturated fatty acid (MUFA).

The essential fatty acids that you can’t live without are PUFA’s including a-linolenic acid (ALA; an omega-3 short chain PUFA) and linoleic acid (an omega-6 short chain PUFA).  These essential fatty acids are the foundation for the formation of long chain polyunsaturated fatty acids or “LC-PUFA’s”.  That being said, LC-PUFA’s are not essential if the short chain PUFA’s are available.  The short chain PUFA’s can be elongated to the LC-PUFA’s in the body but microalgae in the ocean are much more adept at doing this than humans2.  The omega-3 LC-PUFA’s which are much easier to get from fish that eat tons of algae are the 20 carbon eicosapentaenoic acid (EPA) and the even longer 22 carbon docosahexaenoic acid (DHA).  Meats are rich in the omega-6 LC-PUFA with 20 carbons called arachadonic acid.

The final form of fatty acid to explain in the interest of this article is the conjugated fatty acids.  Conjugated fatty acids are those that have 2 C=C’s separated by a single bond.  This isn’t as important as realizing that they come in many isomers which contain the same number of atoms but arranged differently in structure.  The most interesting one of the conjugated fatty acids is conjugated linoleic acid (CLA) derived from meat and dairy products.  CLA comes in two common isomers, cis-9:11 and trans-10:12 that have unique biological properties we will further discuss.

Many studies have indicated that fish oils and CLA supplements have potential in augmenting your training in the gym.  However, for every study supporting the use of these supplements there is at least one that found no effect2.  Athletes have been known to take these supplements to reduce body fat, increase lean muscle mass, reduce muscle damage and inflammation, and improve cardiorespiratory performance.  What does the science really say?

With regards to fish oil there are some theorized and realized effects of supplementation.  The main theory of fish oil supplementation is that it has anti-inflammatory effect that can help limit delayed onset muscle soreness and thus get you back in the gym quicker.  The omega-6 fatty acids have a pro-inflammatory effect so consuming more omega-3 fish oils tips the scales toward an anti-inflammatory environment in your body3.  Ernst and colleagues demonstrated that EPA and DHA supplementation for 3 weeks reduces inflammation after an aerobic challenge4.  Another study on soreness after eccentric (negatives) training compared omega-3’s to a placebo5.  They found significant reductions of inflammatory markers in the blood of subjects immediately after and up to 48 hours after the exercise bout.  Another study on eccentric bicep curls demonstrated similar findings with significant reductions in muscle soreness with 7days of 3g/d of omega-3’s6.

Omega-3’s are able to improve utilization of oxygen and flexibility of red blood cells through integration into their cell membranes.  More flexible cells mean that they can squeeze their way through very small blood vessels in higher concentration carrying more oxygen to muscles.  One study demonstrated that 6g/d of fish oil supplementation for 6 weeks resulted in enhanced oxygen delivery and maximal oxygen uptake during hypoxic altitude training7.

Beyond the clinical trials of fish oil supplementation, there are many laboratory studies that show potential benefit of fish oil on cell cultures.  For instance, one study showed that DHA can enhance lipid oxidation and insulin sensitivity in skeletal muscle cells through AMPK activation8.  Fish oils have also been shown to increase fat oxidation, reduce bodyweight, and prevent weight gain in animal models9.  Even with all the laboratory and clinical evidence suggesting benefits of fish oil, a definitive answer to whether it will help your training is difficult to make.  With little down side, it’s worth a try in my opinion.

CLA is another fatty acid that has great results in animals, with only a few good human trials. CLA supplementation is claimed to improve body composition by helping you burn fat.  Kreider and colleagues at the University of Memphis studied the effects of CLA on performance and body composition in experienced bodybuilders10.  Unfortunately they weren’t able to demonstrate any significant beneficial effects for bodybuilders, but the study had limitations.  On the contrary, studies by Thom et al. and Colakoglu et al. demonstrated that CLA supplementation improved endurance exercise performance and body composition11,12.  Furthermore animal studies demonstrate that the trans-10:12 isomer of CLA reduces fat in mice13.  Unfortunately natural meat and dairy sources of CLA are low in that particular isomer so use a commercial supplement for a mix of CLA isomers.

One thing we as bodybuilders realize is that if you want to build muscle, you must maximize your testosterone levels.  Since testosterone is synthesized in your body from cholesterol, it is not a reach to realize that fats may have a role in testosterone production as well.  Although research on fish oil and CLA’s effect on testosterone production is still in its test-tube infancy, the studies in cell culture are promising.  One study on CLA supplementation (6g/day) demonstrated very small increases in testosterone2.  Although fats improve testosterone production in cell cultures the mechanisms in the body seem a bit more complex.

Side Bar:

Safflower oil has made headlines in the past year, as Doctor Oz has touted its potential to promote weight loss.  Safflower oil is rich in the essential omega-6 fatty acid, linoleic acid (≈78% linoleic acid).  A 16 week study at Ohio State University compared high-linoleic safflower oil with CLA.  The safflower oil intervention reduced belly fat and increased lean mass more effectively than CLA, although CLA did improve fat loss.  However, another study suggested that substituting dietary linoleic acid in place of saturated fats increased the rates of death from all causes, coronary heart disease, and cardiovascular disease. The debate continues.

Norris LE Am J Clin Nutr. 2009 Sep;90(3):468-76

Ramsden CE BMJ. 2013 Feb 4;346:e8707

The omega-6 fatty acid arachadonic acid is thought to be beneficial for bodybuilding by activating protein synthesis through the signaling protein mTOR14,15.   Roberts et al. showed significant improvement in anaerobic sprint capacity with arachadonic acid supplementation16.  Further, data suggests that the prostaglandins from arachadonic acid are able to increase muscle cell growth via cell membrane receptors interacting with the mTOR pathway15.

This is where the Goldilocks principle applies to your training.  Clearly there can be too little or too much of a good thing and finding the “just right” balance is definitely a challenge for us all.  Although all the fatty acids we have discussed here have potential in improving your performance supplementation will have little effect if your diet is out-of-whack.  The American diet typically has ratios of omega-6 to omega-3 in excess of 10 to 1.  It is theorized that humans may have evolved with a diet of a 1-to-1 ratio of omega-6 to omega-3 (Goldilocks?).   The optimum ratio is thought to be at least 4 to 1 or lower for health and longevity.   If you want to try fatty acid supplementation, I suggest that you begin with a clean diet with a combination of fish, lean meats, nuts, and dairy and then augment with the desired fatty acids.



1)  Harden CJ, et al. Long-chain polyunsaturated fatty acid supplementation had no effect on body weight but reduced energy intake in overweight and obese females. Nutrition Research 16 Oct 2013 e-pub

2) Macaluso F, et al. Do Fat Supplements Increase Physical Performance? Nutrients 2013; 5:509-524

3) Fetterman, J.W., Jr.; Zdanowicz, M.M. Therapeutic potential of n-3 polyunsaturated fatty acids in disease. Am. J. Health Syst. Pharm. 2009, 66, 1169–1179.

4) Ernst, E, et al. n-3 fatty acids and acute-phase proteins. Eur J Clin Invest. 1991 Feb;21(1):77-82.

5) Tartibian B, et al. Omega-3 fatty acids supplementation attenuates inflammatory markers after eccentric exercise in untrained men. Clin J Sport Med. 2011 Mar;21(2):131-7

6) Jouris KB, et al. The Effect of Omega-3 Fatty Acid Supplementation on the Inflammatory Response to eccentric strength exercise. J Sports Sci Med. 2011 Sep 1;10(3):432-8.

7) Guezennec C, et al. Influence of polyunsaturated fatty acid diet on the hemorrheological response to physical exercise in hypoxia. Int. J. Sports Med. 1989 Aug,10(4):286–291.

8) Lam YY, et al. Insulin-stimulated glucose uptake and pathways regulating energy metabolism in skeletal muscle cells: The effects of subcutaneous and visceral fat, and long-chain saturated, n-3 and n-6 polyunsaturated fatty acids. Biochim Biophys Acta. 2011 Jul-Aug;1811(7-8):468-75

9) Kopecky J, et al. n-3 PUFA: bioavailability and modulation of adipose tissue function. Proc Nutr Soc 2009 Nov,68(4):361–369.

10) Kreider RB, et al. Effects of conjugated linoleic acid supplementation during resistance training on body composition, bone density, strength, and selected hematological markers. J Strength Cond Res. 2002 Aug;16(3):325-34.

11) Thom E, et al. Conjugated linoleic acid reduces body fat in healthy exercising humans. J Int Med Res. 2001 Sep-Oct;29(5):392-6

12) Colakoglu S, et al. Cumulative effects of conjugated linoleic acid and exercise on endurance development, body composition, serum leptin and insulin levels. J Sports Med Phys Fitness. 2006 Dec;46(4):570-7

13) Park Y, et al. Evidence that the trans-10,cis-12 isomer of conjugated linoleic acid induces body composition changes in mice. Lipids 1999;34:235–41

14) Wen ZH, et al. Critical role of arachidonic acid-activated mTOR signaling in breast carcinogenesis and angiogenesis. Oncogene. 2013 Jan 10;32(2):160-70.

15) Markworth JF, et al. Prostaglandin F2alpha; stimulates PI3K/ERK/mTOR signaling and skeletal myotube hypertrophy. Am J Physiol Cell Physiol. 2011 Mar;300(3):C671-82.

16) Roberts MD, et al. Effects of arachidonic acid supplementation on training adaptations in resistance-trained males. J Int Soc Sports Nutr. 2007 Nov 28;4:21.