The word itself just does not feel good rolling off the tongue.
America's opinion on fat has changed greatly over the last twenty years. As a country we have gone from thinking “fat makes you fat” to “fat burns fat.”
I am relieved to see that the general population no longer abandons fats from their diet. Fat is essential to our survival as it is a major source of fuel, carries out many metabolic processes, protects our organs, makes our skin soft, and makes food taste good! However, I do worry that fat will start to play a larger role in our diets than it should (Jeukendrup & Gleeson, 2010).
With the principle of scarcity, more of one thing means less of another. So, if people start eating more fat, they will start eating less protein and carbohydrates.
At the end of the day your dietary success to grow lean muscle or burn fat will come down to how well you can balance and adhere to the three macronutrients.
Before we dive into how much fat you should eat, let's learn a little bit more about what fat is.
All fats have nine kilocalories per gram. This makes it the most calorically dense macronutrient. This is why foods like almonds, which are generally perceived as healthy, may be dangerous for some people as it is easy to overeat on. By overeating on almonds you may consume a caloric surplus and gain weight.
Fat can be classified in many different ways. You may see it classified by its chain length, saturation level, shape, or by any commercial processing that the fat went through. You are probably the most familiar with hearing about the saturation level of fatty acids. This includes monounsaturated fatty acids, polyunsaturated fatty acids, and saturated fatty acids (Manore et al., 2009).
Monounsaturated Fatty Acids
Monounsaturated fats are the least controversial type of fat that I will discuss. Their structure consists of one carbon double bond per molecule and are liquid at room temperature. Monounsaturated fats are found in plant-based oils like canola oil, olive oil, or sunflower oil (Jeukendrup & Gleeson, (2010).
This is a good type of fat that has been shown to help lower low density lipoproteins (LDL or the naughty cholesterol) which will help lower your risk for cardiovascular disease and stroke (Schwingshackl & Hoffmann, 2014).
The statement that monounsaturated fatty acids are “good” fats is one of the few things people will agree on.
Polyunsaturated Fatty Acids
When discussing polyunsaturated fats, it gets a little more complicated.
Polyunsaturated fatty acids have two or more double bonds per molecule. These fats are typically found in nuts, fish, and plant-based oils like vegetable or corn oil (Manore et al., 2009).
Linoleic acid is a type of polyunsaturated fat and is an essential nutrient because our bodies can not make this on its own. You will typically hear these fats called essential fatty acids (EFA). Linoleic acids are found in the omega-6 fatty acid groups. Some scientists use to believe that linoleic acid was a bad fat because research showed that it contributed to inflammation (Johnson & Fritsche, 2012). This has been highly disproven and in fact a higher intake of omega-6 fatty acids has many health benefits like possibly increasing bone density (Longo & Ward, 2016).
Αlpha-linolenic acid is another type of polyunsaturated fat that is an EFA. An omega-3 fatty acid is an example of an α-linolenic acid and has its first double bond on the third carbon atom. Omega-6 fatty acids will have its first double bond on the sixth carbon atom and omega-9's will have its first double bond on the ninth (Committee on Diet and Health, 1989).
Omega-3 is the group of fatty acids that have received a great deal of attention due to their observed health benefits such as increasing fat loss, decreasing inflammation, and increasing cognitive performance (Muldoon et al., 2010; Couet et al., 1997; Bloomer et al., 2009). We can break α-linolenic acid down into eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (Committee on Diet and Health, 1989).
Now let me tell you a little secret.
The benefits observed in omega-3 comes from EPA and DHA. Think of it like this, EPA and DHA are the tiny cardboard pieces that make up one piece of a puzzle. This piece is the omega-3 fatty acid. Everything else in the article will hopefully help you piece together this puzzle of fats.
Knowing this, is it fair to say that without EPA and DHA we would not experience any of the omega-3 benefits?
You may be asking yourself so what? If I eat or supplement omega-3 in my diet, I will still get EPA and DHA... right?
A problem that exists is in the conversion between α-linolenic acid to EPA and DHA. This is something that our bodies struggle with. Fortunately, diets high in both α-linolenic acid (omega-3) and linoleic acid (omega-6) assists in this conversion. People will argue that it is the ratio of omega-3 to omega-6 that matters but they are wrong. It really is the amount of fat that is important. This is another reason why we should not be worried about eating polyunsaturated fats (Goyens et al., 2006).
Saturated Fatty Acids
Saturated fats will be the most complicated type of fat that we will discuss due to the ongoing debate on how these fats affect your health.
Saturated fatty acids have a single bond attaching the carbon atoms and are filled by hydrogen. This is what makes these fatty acids solid at room temperature. Saturated fats are largely found in animal products such as meats, eggs, milk, and cheese but also in palm and coconut oil.
Saturated fats have received a bad reputation over the years. Early studies performed on saturated fatty acids found a strong correlation between high saturated fat intake and risk of coronary heart disease and stroke (Keys et al., 1966). Current research has pointed out the flaws in these past studies and have redirected our attention to studies that have shown saturated fats to actually decrease a person's risk of coronary heart disease and stroke (Siri-Tarino et al., 2010).
Now this does not mean you should eat as much saturated fat as you want. Balance is going to be key and we must be eating sufficient amounts of polyunsaturated and monounsaturated fats as well. I am just saying that saturated fats are not a fat you need to avoid.
Cholesterol and Saturated Fats
Cholesterol is a the most common type of sterol and is composed mainly of four hydrocarbon rings. While our bodies are able to make cholesterol, it is still healthy to consume because it is required to help build and maintain our cell membranes, make bile, and break down fat soluble vitamins. Cholesterol is found exclusively in animal products (Manore et al., 2009).
Wait, that rings a bell. Aren’t saturated fats found in animal products?
It is this correlation of animal products being high in both cholesterol and saturated fat that have given them a very bad reputation. But like I said, saturated fats are not necessarily bad, and cholesterol is not necessarily bad. In fact, I’ve provided arguments for both of these fats being healthy.
We are slowly starting to see some progress made in switching the general population's perception on saturated fats. In early 2015 the dietary guidelines in America lifted their warning of not eating more than 300 milligrams of cholesterol a day. It is this warning that caused people to limit the amount of whole eggs they consumed due to their high cholesterol.
Scientists have been questioning this limit to egg consumption over the last two decades (Hu et al., 1999). In 2006 a study conducted on over 9,000 participants found that there were no negative health effects between the participants eating one egg a week or six eggs and that there are many beneficial nutrients in egg yolks (Qureshi et al., 2007). This is one example of research being several years ahead of popular dietary guidelines.
Trans Fatty Acids
Trans fats are probably the one fat that your brain instantly registers as the worst thing in the world. It has received a bad reputation due to its effects on increasing low density lipoproteins (the naughty cholesterol) and decreasing high density lipoproteins (the nice cholesterol) This increases your risk of coronary heart disease (Manore et al., 2009).
Trans fats are unsaturated fatty acids that have at least one double bond. This may ring a bell as it is the same structure as polyunsaturated fatty acids. However, polyunsaturated fats have a cis configuration on the same side of the carbon bond while trans fats have a trans configuration on the opposite side of the carbon bond. This one minor difference makes the structure for trans fats more similar to saturated fats (Committee on Diet and Health, 1989).
Where I feel science has failed in campaigning against trans fats is not making a clear distinction between natural trans fats and unnatural trans fats. Natural trans fats may occur in dairy and meat products. Unnatural trans fats may occur in hydrogenated oils which are especially common in fast food.
There was a great deal of initial research on trans fats that showed them to have a negative impact on human health. Unfortunately, these studies have failed to distinguish between naturally occurring trans fats and unnatural trans fats (Chardigny et al., 2008).
One study that established the difference between natural and unnatural trans fats found no significant effect on LDL or HDL when looking solely at naturally occurring trans fats (Chardigny et al., 2008).
When looking at unnatural trans fats, the study found both LDL and HDL to decrease in women, but not men. Rarely have studies conducted on trans fats taken into account gender. This is an interesting study that may suggest that there is an unknown gender mechanism that causes different effects on unnatural trans fats. Another interesting observation was that LDL decreased in women when past studies have shown an increase. However, this is only one study and I do not feel it gives us the right to jump to a conclusion that unnatural trans fats only affects women (Chardigny et al., 2008).
Normally I would also add that we should not jump to the conclusion that natural trans fats are fine to eat, but a literature review did find naturally occurring trans fats to not have a significant effect on coronary heart disease. While it has long been accepted that trans fats lower HDL and raise LDL, this review was unable to find a significant association when observing solely naturally occurring trans fats. In fact, some of the studies that were reviewed observed that natural trans fats lowered a participant's risk of coronary heart disease (Field et al., 2009).
The above research does not mean that I am giving you the green light to go ahead and eat trans fats ab libitum. I am merely trying to point out that trans fats may not be as evil as you think. Further research will be needed to compare different trans fat intake with other fat intake in humans (Field et al., 2009).
I do fully support the Food and Drug Administration's decision to ban trans fats in the United States. There is more than enough evidence to support this decision. I just feel we have a tendency to be swept up in polarizing ways of thinking about nutrition.
But until this ban goes into effect, if you are a healthy individual eating a balanced diet, there is no need to freak out over the one gram of trans fat in your occasional fast food burger.
Evolution Training System Recommendation
Alright, we now know what fat is and that we should eat a variety of fats.
But how much fat should you eat?
The recommended daily allowance (RDA) for fat is to consume 20-35% of your Calories from fat with less that 10% of these Calories coming from saturated fats. I support this recommendation because it gives people the leeway to adjust their fat intake to best suit their needs. Some may prefer high fat diets and others may prefer low fat diets.
However, I do feel the RDA should establish better guidelines for EFA intake and athletes.
Essential Fatty Acid Intake
Remember, linoleic and α-linolenic acid are essential and we need to be eating adequate amounts of both EFAs to assist in the conversion of α-linolenic acid to EPA and DHA. The Dietary Guidelines for Americans (2010) recommends an intake of 250 milligrams of EPA and DHA daily. This may look like two four ounce servings of fish in one week.
For this reason it is important to take note on how much seafood, nuts, flaxseed oil and other fats that are high in omega-3 that you consume. We tend to get enough omega-6 fatty acids in our diets, but often lack consuming enough omega-3 fatty acids. If your diet is lacking this, I would recommend supplementing with fish or krill oil (Yurko-Mauro et al., 2015).
Athletes and Fats
Athletes may find that eating 20% of their Calories from fat is too high. Carbohydrates are our main source of fuel during exercise and elite athletes will want to consume a high-carb, low-fat diet. This has been showed to best fuel athletic performance, maintain muscle, and promote recovery (Burke et al., 2004).
For example, a 160-pound male cyclist who eats 3400 kilocalories a day may have 15% of his Calories come from protein, 20% from fat, and 65% from carbohydrates. Believe it or not, these 550 grams of carbohydrates may not be enough.
This athlete may perform better dipping below the 20-35% RDA.
Research has shown that having fats at 15% is safe and is recommended in certain circumstances (Lambert, Frank & Evans, 2004). So, this athlete could decrease his fat to 15% and increase his carbohydrates to 70% to give him a grand total of 595 grams of carbohydrates a day.
Another circumstance where it may be beneficial to drop down to the 15-20% range is for someone in a caloric deficit. When you are in a caloric deficit your protein needs increase (Helms et al., 2014). As Calories get smaller and smaller, the percentage of Calories coming from protein will get larger and larger.
If you pair this with intense exercise you may find that your carbohydrate intake is getting too low. In this case you will also benefit from lowering fats and increasing carbohydrates.
Are Fats Anabolic?
A popular counterargument for consuming a low fat diet is that fat is anabolic and should be kept high.
Studies have shown that diets high in fat have an anabolic response on the body by increasing levels of testosterone (Dorgan et al., 1996). If you are somebody trying to build muscle it may be tempting to start increasing your fat intake in an effort to become more anabolic.
But before you start gorging on some dark chocolate covered almonds, I would like to point out that naturally increasing hormones such as testosterone and IGF-1 does not have a significant association with increases in strength and muscle mass.
One study found that increasing testosterone and IGF-1 within natural limitations did not have a significant effect on strength. This study did find a small positive correlation when comparing muscle mass to human growth hormone and cortisol (West & Phillips, 2012).
While all of these anabolic hormones do have an effect on hypertrophy, you would have to increase these hormones in an unnatural way. So, if you take steroids you will be able to see benefits from the elevations of these hormones (Hartgens & Kuipers, 2004).
However, if you are taking hundreds of supplements and trying hundreds of different exercises to naturally increase these hormones, you will probably not see any benefit. You can save both your time and your money.
I hope the information above has made you a little more educated on the different types of fats that are on the market. The next time someone tries to preach against saturated fats or naturally occurring trans fats you will have some research to argue against them.
It is important to point out that most fats will have a mixture of monounsaturated, polyunsaturated, and saturated fats. For example, olive oil is seen as a monounsaturated fat but it still gets 14% of its total fat from saturated fats.
All I can say is to try and eat your fat from a variety of sources and balance it with the other macronutrients. Don’t find that one food high in fat and start getting 80% of your fat from it. Eating a balanced diet from a variety of sources is one of the most important things you can do and has been shown to have numerous health benefits (Freeland-Graves & Nitzke, 2013).
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