...and why it's all that
Fats have seen a nice surge in popularity over the past few years. After being vilified in the 80s and 90s as the cause of weight gain (fat makes you fat!), fat caught a break when the blame shifted to carbohydrates. Following that, the trend towards healthy fats and omega-3s (which, if I recall, began with flax oil) started in full, and fat started to get some respect.
Still, some of the old hate remains—for a lot of people, fat is not generally thought of as a nice word, especially if one is trying to drop some extra pounds.
However, your body needs fat to function properly, just as it needs protein. In fact perform a variety of specific and necessary jobs.
But, I’m getting a bit ahead of myself. First and foremost, we should get an overview of what we’re even talking about.
“Fat” is a catch all term for a substance which consists of a heterogenous collection of chemically related substances, the fundamental unit of which is the fatty acid.
Without getting too bogged down in chemistry, a fatty acid is made up of a long chain of carbon atoms on which hydrogen atoms are attached. At one end of the chain is an acid group. There is a lot of potential variation in structure of acids, and that results in a large set of distinct “types” of fats that behave quite differently in the body, but still fall under the term fatty acid.
First, I’ll go into what makes each type different from the rest, and what comprises the distinctions. After that, we’ll discuss them each briefly.
Saturation refers to the amount of hydrogen atoms that are attached to the carbon chain. If all the available space is occupied, the fatty acid is called a saturated fatty acid. If less than the maximum amount is found, then the fatty acid is unsaturated.
Unsaturated fatty acids result from a chemical structure called a double bond. One double bond in the fatty acid results in what is called a “monounsaturated fatty acid”; not surprisingly, if there is more than one bond, we refer to it as a polyunsaturated fatty acid.
This is important because of the way saturation affects the fat, which will in turn determine (to some degree) how that fat will react in our bodies.
One of the most important things to consider is that the degree of saturation influences the melting point of the fatty acid, which we’ll touch on in each section.
But, before we get there, we should touch on why fat is so damn important.
Firstly—and perhaps most important— on a chemical level, fatty acids are an integral component of the plasma membrane of every cell in the body. The composition of the cell membrane in terms of the fatty acids that make up the membrane are known to affect the quality and degree of signaling across the membrane—which is crucial since cellular responses to hormones, uptake of nutrients, and discharge of waste all require activity at the membrane.
Fat has several other functions that are necessary for optimal health.
Fat plays an important role in helping to form the barrier to water in the skin; also fat is also a critical component of nerves which are coated with fat. This coating serves to speed up conduction down the nerve.
A final function of fat is to serve as the substrate for a whole set of hormones known as eicosanoids. Although less well known than some hormones that I’ve written about, eicosanoids are essential for numerous functions that regulate things like blood pressure, inflammation, blood clotting, and labor. In fact, a pregnant, fat-deficient animal cannot go into labor.
Now, from a nutritional standpoint, it may seem somewhat silly to spend so much time talking about fat, when you consider that our bodies can actually manufacture fat as needed; however, the problem is that not all the necessary fats can be produced. More on that below.
Got it? Okay, good.
Now, let’s breakdown the various types of fats, so that you know what’s what.
Monounsaturated fats are found mostly high fat fruits, such as avocados, as well as nuts like pistachios, almonds, walnuts, and cashews. This type of fat can also be found in olive oil.
Monounsaturated fats help lower bad cholesterol and raise good cholesterol, which is a very good thing. It’s also been proven to help fight weight gain, and may even help reduce body fat levels.
As for temperature, monounsaturated fats are typically liquid, particularly at room temperature, but will become cloudy when placed in the refrigerator.
Like monounsaturated fat, this good fat helps fight bad cholesterol. You can find polyunsaturated fats in foods like salmon, fish oil, sunflower oil, seeds and soy.
Polyunsaturated fats contain Omga-3 and Omega-6 fatty acids, which have largely been processed out of our food.
Yes, I’m about to go on the Good Fats Rant. I know this is re-hashing a lot of what you’ve heard, but if I didn’t cover it I wouldn’t be doing my job—so bear with me.
As you probably know, there is a subset of dietary fatty acids, specifically linoleic acid (known as omega-6) and linolenic acid (known as omega-3)—you have probably heard these referred to as “good fats” or even “fat-burning fats.” And of course to an extent, that is true.
More importantly, you’ve heard them referred to as Essential Fatty Acids, or EFAs—which means it’s necessary either consume them in food or through supplementation. The reason is that these CANNOT be manufactured by out bodies, and so it becomes essential to ingest them. Makes sense, right?
Put another way, these two types of polyunsaturated fatty acids that our bodies cannot manufacture are not interconvertible with one another. And so, the important thing to remember is that “good fats” (especially sources high in Omega-3s, like krill oil) are needed by your body to remain healthy and to function at optimal levels. Since these cannot be manufactured, you’ve got to each the right foods or supplement with the right stuff.
Polyunsaturated fats stay liquid even in the cold because their melting point is lower than monounsaturated fats.
I’ll have the most to say about sat-fat, so get ready to read!
Depending on your perspective, saturated fat is either the best, or possibly the worst. No matter what you think about total intake, there are positive aspects to sat-fat; Similarly, however, it gets some bad press because of a few studies. You see, there have been studies (well, one study, really) linking high intake of saturated fats to heart disease.
To give this a bit more context, the whole idea that saturated fat has been “proven” to be anything other than delicious goes back to a pretty flawed research study from the 1950′s where a scientist named Ancel Keys published a paper that laid the blame on dietary fat intake for the increasing heart disease phenomenon around the world.
However, there were major flaws to his study. For one, in his conclusions he only used data from a small portion of the countries where data was available on fat consumption versus heart disease death rate. When researches have gone back in and looked at the data from all of the countries where data was available, there actually was no link between fat consumption and heart disease deaths. In retrospect, it seems that Keys jumped the gun here and landed on conclusions that didn’t really have a basis in fact.
Secondly—and this is really where I think we ought to focus—his blaming of fat intake for heart disease was only one factor that was considered. There was no consideration of other factors such as smoking rates, stress factors, sugar, and refined carbohydrate intake, macronutrient combination, exercise frequency, and other lifestyle factors. In fact, to my knowledge, none of the subjects were at all fit. Eating a bunch of cheeseburgers and not exercising might lead to heart disease, sure.
To drive my point a bit further home, I need to just point out that nearly anytime there is a study which compares subjects who exercise against those who don’t, we are consistently made aware that you really can’t compare to which creatures. Simply put: lifestyle habits completely change the game.
All of which is to say that have yet to see compelling evidence that demonstrates that saturated fat would be truly damaging to people who lead a lifestyle that includes exercise and a generally good diet.
Unfortunately, Keys’s study has been cited for over five decades now as “fact” that saturated fat is bad for you.
As you can see, all of this is ultimately more hypothetical than factual; conclusions that blamed heart disease deaths on fat intake were, in actuality, a shot in the dark about what a possible cause may have been, even though all of those other factors I just mentioned, plus many others, may be (and probably are) the more prominent cause.
Since that time, numerous other studies have been conducted trying to link saturated fat intake to heart disease. The majority of these studies have failed to correlate ANY risk at all from saturated fat. A couple of them made feeble attempts at linking saturated fat to heart disease, however, it was later shown that the data was flawed in those studies as well.
To say I’m not convinced that saturated fat is bad for you might be the understatement of the year; however, research is research and once again, I wouldn’t be doing my job if I didn’t give you all of the information available. So, either you agree with the Keys study or you don’t, and you can structure your intake or avoidance of saturated fat accordingly.
Saturated fat also gets a bit of a bad rap because it has also been shown to elicit and increase in cholesterol in the blood stream. Again, I have to say that this is not as scary as the media makes it seem—cholesterol concerns are a highly overblown.
The truth is, cholesterol actually acts as an antioxidant against dangerous free radicals within the blood and is also necessary for the production of certain hormones that help to fight against heart disease.
When there are high levels of undesirable substances in the blood (caused by the dietary intake of damaged fats, highly processed “unhealthy” foods, and large quantities of sugars), cholesterol levels rise in order to combat these substances.
Having said that, fact of the matter is that foods containing saturated fats are usually pretty calorically dense, as well. Overeating anything isn’t going to lead to fat loss, obviously, and eating very calorically heavy foods is a good way to gain weight–both fat and muscle, depending on a number of other factors.
You can find saturated fats in foods such as dairy, eggs, red meat and some seafood.
While saturated fat can’t be put on our ‘good fat’ list, if consumed in reasonable doses it’s completely fine. However, you can limit your intake by selecting the foods you favor most and avoiding others.
On the more positive side, it should be noted that saturated fats have some pretty positive effects on muscle gain and, consequently, fat loss. I touched on this more completely in this post on red meat.
Saturated fats have a high melting point and consequently are solid at room temperature. The fat that is visible in beef is due to the high content of saturated fat.
And here is the black sheep of the fat family. Trans fats are the worst fats—and in truth, one of the worst “foods”—that you could possibly consume. It’s found in foods such as French fries, potato chips, and most fried food.
While some trace amounts of trans fats are naturally occurring in meats and other food, by and large, most are not naturally occurring. Instead, they are generally man-made.
Trans fats are made by a chemical process called partial hydrogenation. Liquid vegetable oil (an otherwise decent monounsaturated fat) is packed with hydrogen atoms and converted into a solid fat. This made what seemed an ideal fat for the food industry to work with because of its high melting point, smooth texture and its reusability in deep-fat frying.
Essentially, trans fats come about as a result of over-processing our foods in order to offer consumers a longer shelf life.
If your food is pre-packaged, it’s a pretty safe bet it has its fair share of Trans fats. You should try to avoid Trans fats at all costs if you are serious about your goals. Or if you just don’t want to be eating plastic garbage.
Of course, I take a moderate approach. If you’re limiting your intake of junk foods, exercise regularly, get good nutrition otherwise—including a variety of healthy fats—then chances are if you have the occasional Twinkie once every few months, you’ll be okay.
As for energy: fat (all types) yields 9 calories per gram.
NOW! With all of that out of the way, as promised, I’ve got some great recipes for you. One is a delicious smoothie based on the worlds’ second-best sammich, and the other is a delicious pork tenderloin recipe.
Before we get to that, though, you may want to check out my other posts in this series:
These recipes fall under the category of “PROTEIN + FAT Meals” as discussed in my post on macronutrient combination.
And, here we go…
And now for something a little different…
Both of these come from Dave Ruel’s amazing cookbook, Metabolic Cooking.
NOTE: Here is a quick link jump to the entire series: