As mentioned in our prior post on Macronutrients, saturated fat is a fat in which all available molecular bonds are filled, or “saturated” with hydrogen, with a single bond between the carbon pairs. But what does that mean? Several things…differences in the way they deal with heat, how they’re used in our bodies, and how they look as food.
How can I tell if it’s a saturated fat? It’s solid at room temperature. Saturated fat usually comes from tropical oils (coconut and palm) or an animal derived fat (butter, lard). This is because the cellular composition is very stable, making them solid.
How does saturated fat react to heat? Very well! It is the most stable of fats. Since the molecular structure is already “filled” with hydrogen, there is little room for rancidity or oxidation. The structure cannot easily be changed, so it is the safest fat for high-heat cooking.
Monounsaturated fat is a little different than saturated; it has one molecule free of carbon and one double bond. This one “unsaturated” molecule makes it slightly more unstable than saturated fat.
How can I tell it’s a monounsaturated fat? It is liquid at room temperate but solid in slightly cooler temperature, like the refrigerator. The liquid texture is caused by the one double bond, which gives the fat a more “slippery” structure. Almost all foods contain a mixture of fat types, but there is usually a larger percentage of one than the other, (i.e. even cheese has saturated and unsaturated fat.) The foods with the highest amount of monounsaturated fats include olive oil, almonds, avocado, macadamia nuts, and hazelnuts.
How does mono-fat react to heat? It has a lower spoke point, so it’s more sensitive to heat than saturated fat. For cooking, only use for light-stir frying. The one “unsaturated” molecule makes it unstable since that molecule is “empty” and has room to turn rancid or oxidize. Our body can’t use these destroyed molecules. So it is fine to use for light heat, but never use for high heat (such as frying).
Polyunsaturated fat is a string of molecular bonds in which multiple molecules are devoid of carbon and there is more than one double carbon bond. Why does this matter? Because the “empty” or “carbon-less” molecules are very unstable, and can easily turn rancid or be corrupted. Why is that bad? Because our body can’t “use” the destroyed molecules. Although fat has a bad rap, our body has many uses for it. It uses it for fuel, feeds our brain, and builds our cells. The “destroyed” molecules are simply stored as body fat, virtually unable to be used, or they can stick to our arteries. (Yup, it’s not only cholesterol that does that. Hence why hydrogenated oils- which are altered polyunsaturated fats-can cause heart disease.)
How can I tell it’s a polyunsaturated fat? It’s liquid, even in the refrigerator. The oils that contain a majority of polyunsaturated fat are: safflower oil, canola oil, sunflower seed oil, flax oil, etc.
How does polyunsaturated fat react to heat? It’s very sensitive to heat. In fact, it’s so sensitive, it can be destroyed by simply the extracting process. So when you buy it, it’s often already rancid, unless the company specifically processes it carefully. Since there are multiple “empty” molecules in the chain, the molecules are that many times more likely to be destroyed and oxidized.
The famous Omegas. You have probably heard a lot about Omega 3 fatty acids, and maybe also Omega 6, Omega 9, and so on. These important fatty acids are polyunsaturated fats, although they occur in varying amounts in certain foods. They are also very important for heart health, brain function, and energy levels. (We will devote an entire blog post to these guys at a later time.) The most important fact to remember for now- they are VERY sensitive to heat, and you can get them in more than just fish oil. Stay tuned for more info.
Trans Fat/Hydrogenated Oils:
These toxic fats have gotten a lot of media attention in recent years. Hydrogenated oils are made by heating polyunsaturated fats to a high heat, then putting hydrogen through them. This makes an otherwise liquid fat into a solid one, trying to emulate butter. The problem is, it turns the fat into trans fat, and creates a kind of rancid, poisonous fat. Hydrogenated fats are closer to plastic than to food.
What are the negative effects? The oils are transformed, and our bodies don’t know how to use them. They enter our fat cells, but then can’t be burned for fuel like normal dietary fat, so they stay there. Also, they have no nutritional value. They hold our fat cells hostage, and give our bodies nothing in return. Not only that, the destroyed fats stick to our arteries, increasing the risk for heart attacks, hypertension, and high cholesterol. Hydrogenated oils are illegal in many countries, so I suggest following suite.
What contains hydrogenated oils? Margarine, and most processed food. Unless you shop primarily at Whole Foods or health food stores, always check labels!! It’s worth avoiding these toxic little devils.