Lipids and Triglycerides
Fats, more technically called lipids, come in a wide variety of shapes and flavors. Most of the different fats that we eat are called triglycerides, which are compounds that contain an alcohol called glycerol and three fatty acids. By the definition, you should see where the term 'tri'-'glycer'ides came from as there are three ('tri') fatty acids attached to a 'glycer'ol.
But that's enough of the overtly complicated stuff. Let's talk about the more commonly used terms when we describe the different kinds of fat.
Saturated and Unsaturated Fat
You've undoubtedly heard of one type of fat, called saturated fat. Saturated fat is a type of fat that doesn't have double bonds in its structure. A double bond gives fat a little kink, twist, or turn in its structure. This means that a saturated fat is like a straight line.
This is in contrast to unsaturated fat, a type of fat that contains one or more double bonds in its structure. When there's only one double bond, it's termed a monounsaturated fat. When there's more than one twist or kink, then it's a polyunsaturated fat. In either case, owing to these chemical double bonds, the fat is kinked and twisted and turns every which way. Polyunsaturated fats just have a lot more twists and turns than a monounsaturated fat. It's like a line that zigzags all over the place nonstop.
Ok, knowing all of this, think about the time you left some animal fat out in a pan you were frying bacon in. Can you recall what happened when the plate cooled down to room temperature? The fat solidified into this white thing. But if you were to go right now to your pantry and find some vegetable oil you'll see that it's still liquid at room temperature.
Which fat do you think is the unsaturated fat? It's the vegetable oil. That's because the kinks and twists in unsaturated fat prevent those fat molecules from neatly sticking to one another into a neat, orderly, and therefore solid structure.
Trans-Fatty Acids and Omega Fatty Acids
When unsaturated fats have hydrogen added to them, through a process called hydrogenation, a trans-fatty acid, aka trans-fat, is formed. Namely, the oil that is hydrogenated is vegetable oil, and hydrogenation makes the resulting fat less likely to spoil but more solid in composition than it was before.
Other than what I've mentioned already, other types of fats you may have heard of are omega-3 fatty acids and omega-6 fatty acids. These guys are unsaturated fats. They're important to know because two polyunsaturated fats, alpha-linolenic acid, a type of omega-3 fatty acid, and linoleic acid, a type of omega-6 fatty acid, are essential fatty acids. Meaning, they must be obtained from the diet because our body cannot make them.
Impact on Health
Fat, in general, plays important roles in our body. Fat helps insulate the body, cushions internal organs, and helps us absorb important vitamins such as vitamins A, D, E, K. But not all fats are equal, and many, especially when ingested in high quantities, may result in weight gain or even more serious health problems. Other than obesity, too much intake of fat can result in things such as arthritis by way of damaging your joints as a result of having to carry around excess weight.
Further still, improper fat intake increases the levels of cholesterol, a fat-like substance that helps to keep your body functioning properly but too much of which can lead to heart disease. Bad cholesterol is known as low-density lipoprotein or LDL. Good cholesterol is known as high-density lipoprotein or HDL. Since the word 'low' usually has a negative or bad connotation, then it's easy to remember which type of cholesterol is bad - it's the LDL.
Eating solid fats, that is to say saturated and trans-fats, increases the amount of this bad cholesterol. This causes the formation of things called plaques in the arteries of the body, resulting in a condition called atherosclerosis. Atherosclerosis causes the arteries, critically in the heart, to narrow and harden. This can lead to a heart attack and death.
Trans-fats are even worse for you than saturated fats, because while saturated fats increase bad cholesterol, trans-fats do this as well while simultaneously decreasing the levels of good cholesterol.
On the flip side, unsaturated fats help to lower the bad kind of cholesterol, which is good!
Sources and Amounts of Fat
Based on that, you already have a pretty good idea that overall, saturated and trans-fats are bad for you and unsaturated fats are good for you. Now it's time to determine where each is found so you can consume more of the latter and less of the former two.
Unsaturated fats are found in fish, walnuts, flaxseed, olive oil, canola oil, avocado, and vegetable oil.
Saturated fats are found in meat, milk, cheese, and other animal products.
Trans-fats are many times added to margarine, cookies, frozen pizzas, and fast food items, like fried chicken or French fries.
While fat provides more energy per unit weight than either carbohydrates or proteins for our body, as you can tell, too much of a good thing is actually quite dangerous. Especially if it's coming from fast food.
Therefore, no more than 20-35 percent of daily caloric intake should come from fat. This means that on a 2,000 calories diet, no more than 400 calories should come from fat we're if using 20% as our rule. You can divide this number of calories by 9, since there's 9 calories in a gram of fat, to come to the realization that that equates to 44 grams of fat per day.
Furthermore, as you should already be all too aware of, the majority of this fat should come from plant- and fish-based sources to maximize the number of unsaturated fats and minimize the number of saturated and trans-fats.
Lesson Summary
In summary, fats are more technically called lipids. Most of the different fats that we eat are called triglycerides, which are compounds that contain an alcohol called glycerol and three fatty acids.
The fats we consume are grouped as saturated fat, a type of fat that doesn't have double bonds in its structure, unsaturated fat, a type of fat that contains one or more double bonds in its structure, or trans-fat, which is hydrogenated unsaturated fat.
Eating too much saturated and trans-fat leads to improper increases in the levels of cholesterol, a fat-like substance that helps to keep your body functioning properly, but too much of which can lead to heart disease. Specifically, these types of fat increase bad cholesterol, which is known as low-density lipoprotein, or LDL.
Good cholesterol, by the way, is known as high-density lipoprotein, or HDL, and trans-fats lower this kind of cholesterol.
Unsaturated fats are found in fish, walnuts, flaxseed, olive oil, canola oil, avocado, and vegetable oil.
Saturated fats are found in meat, milk, cheese, and other animal products.
Trans-fats are many times added to margarine, cookies, frozen pizzas, and fast food items, like fried chicken or French fries.
Learning Outcomes
Once you watch this lesson in this entirety, you could:
- Discuss the differences between saturated, unsaturated and trans-fats
- Recall some of the sources of the different types of fats
- Detail the benefits and downsides of each type of fat
