Despite years of anti-fat sentiment, it's becoming clear that the right kinds of fats can make you healthier, smarter, more muscular, and leaner.

Back in the 80's, the US Surgeon General's office, the American Heart Association, and the US Department of Agriculture joined forces and took up arms against what they considered to be the great nutritional scourge – dietary fat. That's right, they attempted to eradicate dietary fat from our nutritional lexicon with extreme prejudice.

If you're too young to remember this phenomenon, it might seem downright foolhardy to attack an entire macronutrient category. In fact, waging war against one-third of the macronutrient triumvirate may even seem unthinkable. But to those nutrition conscious individuals living through the war on fat, it's hard to forget the sensationalistic demonization of dietary fat and the faddish low fat diets that followed.

So how did this all come about? Well, back in the 80s, doctors and researchers, alarmed by the rising incidence of heart disease and obesity, needed a strategic target. As lipid researcher Lonnie Lowery has put it, they needed a perfect enemy. So after finding out that the plaques building up in our arteries (arteriosclerotic plaques) were made up of fats and then discovering that certain countries with diets high in animal fat also had a higher incidence of heart disease, 20 subsequent years of scientific investigation were spent attempting to prove that dietary fat (specifically saturated fat and cholesterol) was leading the heart disease brigade.

Interestingly, this science never quite produced any convincing data demonstrating a direct link between dietary fat and heart disease. Ironically though, in the land of "innocent until proven guilty," dietary fat was convicted guilty of mucking up our arteries without any proof. And not only was fat convicted of damaging our blood vessels and our hearts, it also became associated with stroke, obesity, and a host of other maladies that many currently associate with eating "greasy food".

This story becomes even more disconcerting when we realize that despite the clear lack of evidence implicating dietary fat as a cause of the aforementioned health concerns, public health officials at the American Heart Association spoke out on fat, recommending fat avoidance and claiming that compliance with these fat avoidance strategies would lead to the conquering of arteriosclerosis by the year 2000. But here we are, 5 years past the AMA deadline for atherosclerotic obscelescence, and we've only gotten worse.

Did we drop the ball? Have we failed to comply? Heck no! Through the 80s and 90s, anti-fat campaigns were very effective in "helping" us reduce our fat intake from 40% of our diets to 32%. They also "helped" us reduce our cholesterol intakes. But despite these decreases in fat and cholesterol intake (and subsequent increases in the intake of sugar and the more harmful trans fats), heart disease incidence remains high. Add to this the fact that the incidence of obesity has doubled from 15% to 31% during this time and you've got a compelling reason to believe the experts were wrong about dietary fat. In accordance with this idea, Walter Willett, Chair of the Department of Nutrition at the Harvard School of Public Health had this to say:

"The idea that all fat is bad for you, the exclusive focus on adverse effects of fat may have contributed to the obesity epidemic...The emphasis on total fat reduction has been a serious distraction in efforts to control obesity and improve health in general."

So maybe fat ain't so bad. On the contrary, maybe some fats are – gasp – good for us. And that's not just my assessment. Many current scientific teams have dropped their previously flawed hypotheses about dietary fat and cholesterol and have switched sides, realizing that, as Walter Willet indicated, not all fats are bad.

Furthermore, they are beginning to understand that dietary fats, when used properly, can be a strong ally, rather than a deadly foe. Of course, it is true that certain fats probably do plug up our arteries, make us fatter, and accelerate our aging. But it's also true that many other dietary fats can offer protection against heart disease, free radical damage, and cancer; can increase metabolic rate and fat burning; can increase muscle mass; and can increase the production of hormones like testosterone.

Isn't it time you learned to separate the good fats from the bad?

Fat Basics

It's no surprise that many people are confused about fat. Media attention has oversimplified fats so much so that most people believe that all fats are the same and, therefore, bad. As indicated earlier, some fats in our diets are less than desirable (can you say cheese fries?) but just because some fats are counterproductive to our physique goals and our health, branding all fats as bad is the equivalent of macronutrient bigotry.

As with sexism, racism, and nationalism, the key to preventing wide scale "macronutrientism" is information. So dig into these 10 fat basics and learn that all fats were not created equal.

Fat basic #1:

Dietary fat as well as belly fat are packaged as triglycerides. Triglycerides are made up of 3 fatty acids attached to a single backbone known as glycerol (seen below).

The three aforementioned fatty acids attach to each of the carbons by displacing the OH groups on the right side of the glycerol molecule and docking onto the glycerol to form these tri (meaning three) - glyerides.

Fat basic #2:

The fatty acids that join to glycerol are, in general, long strings of carbon molecules (between 4 and 24 carbons in length) with a bunch of hydrogen molecules attached. As many of you may know, there are three main types of fatty acids – saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids.

Below is an example of a saturated fatty acid:

The left end of all fatty acids contains a methyl group that is made up of a C (carbon) with 3 H (hydrogen) attached. The right end of all fatty acid molecules contains a carboxyl group that is made up of a C single bonded to an OH (hydroxyl) group and double bonded to an O (oxygen).

What makes the fatty acid in this example saturated is the fact that all the "middle Cs" have single bonds and have the max number of H attachment. In other words, single bonded hydrogen molecules saturate the carbons. This saturation makes this type of fat very firm and stable. And that's why foods containing a large number of saturated fatty acids are solid at room temperature.

Below is an example of a monounsaturated fatty acid:

These fatty acids are identical to the fat above but have a double bond somewhere in the middle. As a result, they have 2 fewer H groups. Since mono means one, it should be clear that monounsaturates contain one area of unsaturation. While structurally similar to saturated fatty acids, foods containing a large number of monounsaturated fatty acids are liquid at room temperature.

Below is an example of a polyunsaturated fatty acid:

These fatty acids are again similar to the other two types but have more than one double bond. As a result, they also have H groups than the other fatty acids due to their many areas of unsaturation. Like foods high in monounsaturated fatty acids, foods high in polyunsaturated fatty acids are liquid at room temperature.

Fat basic #3:

Whole foods and their triglyceride (fat) components rarely contain a single type of fatty acid. For example, while most nutritionists condemn animal fat as full of heart-clogging saturated fatty acids, only 55% of beef fat is saturated. The remaining 45% come from monounsaturated fatty acids (40%) and polyunsaturated fatty acids (5%). And egg yolks contain only 39% saturated fatty acids. The other 61% come from monounsaturated fatty acids (43%) and polyunsaturated fatty acids (18%). That's right, both beef and egg triglycerides contain both saturated fatty acids and unsaturated fatty acids attached to those 3-carbon glycerol backbones.

Fat basic #4:

Digestion in our gastrointestinal tract breaks down triglycerides into their glycerol and three fatty acid components. Once these "free" fatty acids are let loose, they perform a number of functions from finding their way into cell membranes, being metabolized into inflammatory mediators, binding to DNA to upregulate metabolic machinery, being metabolized for energy, or being repackaged into new triglycerides for intramuscular or adipose tissue fat storage.

Fat basic #5:

Not all three of the triglycerides on the glycerol backbone are readily absorbed. That's right, the body likes absorbing certain fats based on where they were docked on the glycerol molecule. Specifically, the fatty acids in the middle position on the glycerol molecule (this is called the sn-2 position) are digested and absorbed more readily than the other fats. This means that some highly saturated triglycerides might actually behave like triglycerides with more monounsaturated fatty acids or polyunsaturated fatty acids when these types of fats occupy the middle, or sn-2 position, of the glycerol backbone.

Fat basic #6:

The popular omega 3 fatty acids are special types of polyunsaturated fatty acids (multiple double bonds) in which the double bonds begin at the 3rd carbon from the left (methyl group). Because of this the relatively unique position of the double bond and the fact that our bodies cannot make fats with a double bond in that position, omega 3 fatty acids are termed "essential fatty acids" and we must ingest them in our diet lest we develop a fatty acid deficiency.

Alpha-linolenic acid is the main type of omega 3 fatty acid necessary in our diets. Once we ingest this type of fat, the other omega 3 fatty acids can be made via elongation reactions (adding carbons to the chain) and desaturation reactions (creating more double bonds) later on in the chain. Two other omega 3s that have received a lot of attention lately are EPA and DHA. These fats are simply elongated and desaturated versions of alpha-linolenic acid.

Fat basic #7:

The popular omega 6 fatty acids are special types of polyunsaturated fatty acids (multiple double bonds) in which the double bonds begin at the 6th carbon from the left (methyl group). Because of this the relatively unique position of the double bond and the fact that our bodies cannot make fats with a double bond in that position, omega 6 fatty acids are termed "essential fatty acids" and we must ingest them in our diet lest we develop a fatty acid deficiency.

Linoleic acid is the main type of omega 6 fatty acid necessary in our diets. Once we ingest this type of fat, the other omega 6 fatty acids can be made via elongation reactions (adding carbons to the chain) and desaturation reactions (creating more double bonds) later on in the chain. Another omega 6 that has received a lot of attention lately is arachidonic acid. This fat is simply an elongated and desaturated version of linoleic acid.

Fat basic #8:

Humans evolved on a diet with a 1 or 2:1 ratio of omega 6 to omega 3. Modern diets have a ratio of 20 or 30:1 in favor of omega 6 fatty acids and this ratio is believed to be a significant contributing factor to the development of many diseases.

Fat basic #9:

Trans fats are made by bombarding polyunsaturated fatty acids with hydrogen molecules until they become more hydrogenated or, as discussed earlier, saturated with hydrogen.

Therefore, when you see the words "partially hydrogenated," you're looking at trans fats. These fats are called "trans" fats because when they are bombarded with hydrogen, they take on a different shape than other fats with similar degrees of saturation. Many experts implicate trans fats in many disease states.

Fat basic #10:

There are many types of fatty acids within each structural category. While most people will be impressed if you show your knowledge of the big three (saturates, monounsaturates, and polyunsaturates), a true fat aficionado knows that there are many different types of fatty acids in each category, each fat with slightly different properties (i.e. carbon chain length).

So next time you're out on a date; impress your lady with your knowledge of the different types of naturally occurring fats as well as the man-made kind. The following chart will provide a quick reference guide.

Types of Fat Common Names (# of Carbon) Prominent Sources
Saturated Fats 1) Myristic Acid (14)
2) Palmitic Acid (16)
3) Stearic Acid (18)
4) Arachidic Acid (20)
5) Lingoceric Acid (24)
1) Coconut and Palm oils
2) Animal fats
3) Animal fats
4) Peanut oil
5) Animal fats
Monounsaturated Fats 1) Palmitoleic Acid (16)
2) Oleic Acid (18)
1) Fish oil
2) Plants and animals
Polyunsaturated Fats Type 1
Omega 3 Fats
1) Alpha Linolenic Acid (18)
2) EPA (20)
3) DHA (22)
1) Plant fats – flaxseed
2) Fish oil
3) Fish and other animal
Type 2
Omega 6 Fats
1) Linoleic Acid (18)
2) Arachidonic Acid (20)
1) Corn, safflower, soy
2) Animal fat
Trans Fats 1) Hydrogenated Vegetable Oils (?) 1) Processed vegetable fat

Eating Fat To Lose Fat

To lose fat, sometimes you have to eat fat. I know, I know, this statement just "feels wrong." After all, years of anti-fat campaigning have convinced us that fat is what makes us chunky. But did you know that monounsaturated fats and certain polyunsaturates actually speed up the metabolic rate? Eric Noreen, a lipid researcher at the University of Western Ontario, believes that the best of the fat burning bunch are the highly unsaturated omega 3s called EPA and DHA. According to Eric, these omega 3 fatty acids can potentially help burn blubber through 3 different mechanisms.

1. Allowing the body to burn fat in situations where fat oxidation (or fat burning) is normally turned off. Normally, when you eat carbohydrates, fat burning is slowed or turned off. Also, during high intensity exercise, the body prefers burning carbohydrate to fat. Therefore in both scenarios, fat burning is dramatically reduced. However, cells that receive a high daily dose of omega 3s actually burn more fat in both situations. The net result – more fat burned each and every day whether you're exercising or not.

2. Increasing your sensitivity to the hormone Insulin. Insulin is both a storage hormone and an anti-breakdown hormone. When insulin goes up, a consequence of eating, ingested nutrients are stored in muscle cells and in fat cells. Likewise, nutrients already in these cells (especially the fat in our love handles) are retained as a result of this insulin boost. Since omega 3 fatty acids can make your body more sensitive to insulin, meaning that less insulin will be released each time you eat, a diet high in omega 3s helps prevent large insulin increases with eating. If insulin is properly managed, more stored fat is released each day. And guess what happens to that fat. You got's incinerated.

3. Increasing the heat of your cellular furnaces. In your cells, there are two metabolic organelles responsible for burning fuel to make energy. The most well known is the mitochondrion while the lesser known one is the peroxisome. Omega 3 fatty acids have been shown to increase the size of both metabolic fires, leading to an increase in the amount of energy burned in each organelle. What this means is that a diet high in omega 3s can make you a fat burning machine.

In a series of investigations conducted by Eric and his colleagues at the University of Western Ontario, Eric showed that a diet supplemented with omega 3-rich fish oil promotes losses of body fat with simultaneous gains in lean mass. That's right, more muscle and less fat, baby.

In addition to omega 3 fatty acids, several other fats have been shown to reduce body fat. The polyunsaturated fat CLA (conjugated linoleic acid – a conjugated omega 6 fat) has shown promise, as have foods high in monounsaturated fats – like olive oil. MCTs (medium chain triglycerides) are also noteworthy. These unique fats have a shorter chain length than many of the other fats discussed in this article. As a result of their unique structure, they are more readily burned than the other types of fat, meaning more energy with less fat storage.

Of course, if you overeat on any macronutrient, you're going to store body fat not lose it. So pay careful attention to your total energy intake and, as Walter Willett suggests, try to get somewhere between 25% and 35% of your daily energy from fat.

Eating Fat To Gain Muscle

For starters, it takes a lot of energy to build muscle. Since fat contains twice as much energy per gram than carbohydrates or protein, fat's a great source of muscle building power as long as you're eating the right kinds and exercising regularly. Also, when compared to protein and carbohydrate, fat is the least costly macronutrient to digest, absorb, and metabolize (called the thermic effect of feeding). This means that fat takes less total energy to break down and therefore more of the energy consumed as fat can go toward muscle repair and growth.

So what are the right kinds of fat for building muscle? Lonnie Lowery tells us:

"All fats supply caloric density for supporting the energy-costly process of protein synthesis. This is a boon for thin, ectomorphic guys trying to gain weight. But since we Americans consume far too many trans fats and omega-6 type fatty acids, an increased focus on monounsaturated fatty acids (e.g. olive oil) and omega-3 fatty acids like flax and (especially) fish oils are even better."

Also, if you're looking for an additional anabolic drive for training hard and building muscle, look no further than your refrigerator. Research published in journals such as the American Journal of Clinical Nutrition and the Journal of Steroid Biochemistry has indicated that a decrease in dietary fat intake as well as a decrease in saturated fat intake can lead to reductions in the blood concentrations of Testosterone and other androgens. Couple your low fat diet with a high carbohydrate/fiber diet and you've got a double dose of androgenic disaster. So when trying to gain muscle, eat your fats, not your Wheaties, lest you skip the gym in favor of antiquing.

Eating Fat To Prevent Heart Disease

Heart disease is considered by some to be an inflammatory disease. Small injuries to the walls of the blood vessels can cause inflammation and the accumulation of fatty deposits. In an environment in which blood platelets are excessively sticky and aggregate around the injury and one in which blood clots readily form; the risk for an eventual cardiovascular event is high.

As discussed earlier, omega 6 fatty acids can promote increased inflammation, platelet aggregation, and blood clots, while omega 3 fatty acids reduce all three. Therefore a good anti-atherosclerotic strategy would be to consume a ratio of omega 6 to omega 3 in the 1 or 2:1 range.

In addition to reducing the atherosclerotic potential of the blood vessels, it's also important to balance out the ratios of LDL cholesterol (the bad kind) and HDL cholesterol (the good kind), these ratios being highly associated with heart disease risk.

According to Cassandra Forsythe, a lipid researcher at the University of Connecticut, it's important to get about 30% of your daily energy from fat, but rather than eating any old fats, it's important to get your fat breakdown just right. In her opinion, the best blood lipid profile is obtained when saturated fatty acids make up 30% of total dietary fat, monounsaturated fatty acids make up 40% of total dietary fat, and polyunsaturated fatty acids make up 30% of total dietary fat. Think of this as "The Zone" of dietary fat.

Eating Fat To Treat Cancer

There are probably many causes of cancer including environmental, genetic and some interaction of the two. But regardless of the cause, dietary fat can impact the course of cancer development and the course of cancer therapy.

When cancer cells are exposed to large amounts of omega 6 fatty acids (linoleic acid), they rapidly increase their rate of cell division and growth. On the contrary, when exposed to omega 3 fatty acids, cancer cells become starved of linoleic acid and begin to die. Furthermore, omega 3 fatty acids can upregulate the genetic material necessary for the destruction of cancer cells and block the adhesion of cancer cells to other health cells. Couple these facts with the fact that omega 3 fatty acids can increase the effectiveness of traditional cancer treatments and the survival rates of patients on traditional cancer treatments and it looks like omega 3 supplements should be the mainstay of any cancer treatment.

Eating Fat To Keep You Young

Sooner or later we all have to face the facts – we're all getting older. But getting older doesn't necessarily mean dramatic cognitive and physical decline. Although scientists can't determine exactly what makes us grow older, one prevalent theory is the free radical theory of aging. This theory states that aging is a process accelerated by the constant bombardment of our genetic material by free radicals. These free radicals can damage DNA, leading to defects in gene expression and eventual decline.

If there were a way to upregulate cellular protection from free radicals, we might age more gracefully. Well, there are two ways. First, exercise acutely increases oxidative stress on the body (free radical accumulation). But after a very short period of time, the body upregulates the cell's antioxidant mechanisms, leading to an overall greater net oxidant protection.

Interestingly, polyunsaturated fatty acids do the same thing. Although many experts have objected to polyunsaturated fatty acid supplementation because of the fact that polyunsaturated fatty acids are easily oxidized and would theoretically be more subject to free radical damage than monounsaturated fatty acids or saturated fatty acids, these experts are not thinking correctly. Just like with exercise, polyunsaturated fatty acid intake acutely increases oxidant stress but after a very short period of time, the intake of polyunsaturated fatty acids leads to a net increase in oxidant protection. So exercise and eat your polyunsaturated fatty acids in order to stay young.

Eating Fat To Make You Smarter

Although it's unlikely that a dietary change will take you from Fat Albert to Albert Einstein, new data have indicated that the intake of specific polyunsaturated fatty acids (namely the omega 3 fatty acid DHA and the omega 6 fatty acid arachadonic acid) may enhance cognitive development in babies. Infants fed formula deficient in these fatty acids perform more poorly on a number intelligence and vision measures when compared to infants fed formula enriched with these fatty acids or fed breast milk.

In addition, some researchers have speculated that some of the cognitive decline seen in the elderly could be related to dietary fat intake. In a study conducted at Institute of Public Health and the Environment in the Netherlands, researchers found that high omega 6 (linoleic acid) consumption was associated with cognitive decline while high omega 3/fish oil intake was negatively associated with cognitive decline.

Fats To Avoid

As discussed earlier, trans fats are man-made fats created when polyunsaturated vegetables oils (high in omega 6 fatty acids) are bombarded with hydrogen molecules until they become more hydrogenated or, as discussed earlier, saturated with hydrogen. Of course, this hydrogenation makes them behave like saturated fat, making them hard at room temperature.

As you've seen throughout this article, although a small amount of omega 6 polyunsaturated fats are necessary, neither me, nor your body are big fans excess consumption of them. However, taking these fats, blasting them with hydrogen molecules, and altering their structural properties makes them far worse than any naturally occurring fat. According to a paper published in the American Journal of Clinical Nutrition, 30,000 premature deaths per year are attributed to trans fats. Here are the 4 main problems with trans fats:

1) The naturally occurring essential fatty acids are destroyed when fats are hydrogenated. So when you eat trans fats, you actually displace essential fats from your diet.

2) After hydrogenation, trans fats become similar to saturated fats but their structure lacks the metabolic activity of saturated fats. In other words, these fats stick around in the blood for much longer and are more likely to clog up the arteries or be stored as body fat.

3) After hydrogenation, trans fats actually inhibit desaturase activity, limiting the amount of EPA, DHA, and arachidonic acid formed from omega 3 (alpha linolenic acid) and omega 6 (linoleic acid) precursors.

4) Trans fats increase LDL (bad cholesterol) while decreasing HDL (good cholesterol).

Want to know if trans fats are affecting your health? Well, try these facts on for size:

1) Most North Americans consume 10-15 g of trans-fatty acids per day. Ideally we should consume none (or at least less than a gram).

2) The following food choices provide 20 g of trans-fatty acids per day:

2 microwave waffles (4.5 g)
1 small (1 serving) bag of chips (8 g)
1 order of french fries (4.5 g)
1 tablespoon margarine (3.5 g)

3) Products that claim to be "Cholesterol Free" and "Low in Saturated Fat" often have the most trans-fatty acids. Unfortunately these are the products that most of the public thinks are "healthy."

So I hope it's clear that trans fats have absolutely no place in the diet. Very few foods are ever considered universally bad, but trans fats might just be one of them. As far as the rest of your diet, there are no other naturally occurring fats that you should always avoid as long as you take a balanced approach to fat intake. In my estimation, a diet containing 25-35% of the total energy from fat is optimal. Once you get this right, the next step is to consciously attempt to get about 1/3 of your fat from saturates, 1/3 from monounsaturates, and 1/3 from polyunsaturates (with a 50:50 ratio of omega 3s and omega 6s).

Dietary Recommendations

Before you get too wrapped up in debates about what types of fats should be eaten and what types should be avoided, it's important to learn which foods contain which fatty acids. As Peter Lemon, exercise nutrition researcher says, "we don't eat calories, proteins, fats, or carbohydrates...we eat food!"

Use this handy chart below to learn which fatty acids are found in a number of common foods. By learning which foods contain which fatty acids, a balanced fat approach should be a snap. Remember, your goal is to consume 1/3 of your fat from saturated fatty acids, 1/3 from monounsaturated fatty acids, and 1/3 from polyunsaturated fatty acids.

Food % Saturated Fat % Monounsaturated Fat % Polyunsaturated Fat
Almonds 10% 68% 22%
Beef 55% 40% 4%
Brazil Nuts 26% 36% 38%
Canola Oil 5% 57% 38%
Cashews 20% 62% 18%
Cheese 67% 26% 7%
Chicken 31% 49% 20%
Coconut Oil 86% 9% 5%
Duck 35% 52% 13%
Eggs 39% 43% 18%
Flax Seed Oil 8% 18% 74%
Hazelnuts 8% 82% 10%
Herring 22% 55% 18%
Macadamia Nuts 16% 82% 2%
Milk 67% 26% 7%
Olive Oil 13% 75% 12%
Palm Oil 50% 41% 9%
Peanuts 15% 51% 34%
Pecans 8% 66% 26%
Pine Nuts 15% 40% 45%
Pistachios 13% 72% 15%
Pork / Lard 40% 48% 12%
Salmon 20% 30% 40%
Sesame Oil 15% 42% 43%
Walnuts 10% 24% 66%

At this point, I wish I could promise you it will be easy to balance out your fat intake as discussed above. But I can't. At first it will require a bit of conscious awareness with respect to dietary fat. Making the transition from eating sub optimally to eating correctly is never smooth and easy. But if you make the conscious effort, you'll end up smarter, healthier, and better looking. That's gotta be worth the effort, right?

John Berardi, PhD, is the founder of Precision Nutrition, the world's largest nutrition coaching and education company. Berardi advises organizations like Apple, Equinox, and Nike. He's coached the San Antonio Spurs, the Carolina Panthers, US Open Champ Sloane Stephens, and 2-division UFC Champ Georges St-Pierre.