Fat has come a long way. Vilified decades ago as the reason for America’s expanding waistlines, the “low-fat” craze caught fire and burned strong for several years. The only problem was that it was dead wrong. One harpoon was thrown through the idea by the finding that Inuit peoples of the Arctic ate a diet compromised of an enormous amount of fat, yet had little incidence of heart disease. This was because they ate mostly fish fat which kept their hearts and arteries healthy. Fat has always been and should always be a large part of the human diet. And if consumed from the right sources, it is one of the healthiest foods on the planet.
So some fats are good, and some fats are bad. This you may know. But it can often be confusing to try and sort out which fats are “good” and which fats are “bad.” So let’s chew the fat, so to speak.
Perhaps the easiest way to determine between a good and a bad fat is to identify it as either an animal or plant source. If the fat comes from the animal kingdom, it will be higher in saturated fat, a type of fat that increases both bad (LDL) and good (HDL) cholesterol. A little bit of saturated fat is essential, but most Americans eat way too much. Saturated fats increase blood cholesterol more than dietary cholesterol does. Over consumption of this type of fat is a major contributor to cardiovascular disease. So fat from beef, pork, and dairy products like cream, milk, and cheese are all going to contain a large amount of bad fat. The one exception to this is the fish branch of the animal kingdom. Fat from anything that lives in water is extremely healthy and should constitute a consistent part of your diet. When it comes to salmon, mackerel, and anchovy (try a pickled Italian white anchovy and then tell me anchovies are gross), eat up early and often.
On the other hand, if the fat source comes from the plant kingdom, you can be sure that it is lower in saturated fat, and higher in mono- and poly-unsaturated fats, both of which are much healthier than their saturated cousins. Unsaturated fats decrease bad cholesterol and are protective against cardiovascular disease. They also help keep your eyes, brain, skin, and hair healthy. Olive oil is of course the gold standard for vegetable fats, being very low in saturated fat and high in mono-unsaturated fat. But canola oil, sunflower oil, soybean oil, peanut, and corn oil are all healthy as well. I see nothing wrong with a French fry that was made in fresh vegetable oil. However, it is important to be aware that vegetable frying oils hydrogenate over time, which makes them increasingly unhealthy. Hydrogenated oils contain trans fat, which needs to be mentioned. Trans fats are fats that have had hydrogen bubbled through them to make them more stable. The cost of this is that it makes them exceptionally unhealthy. Because we have only started eating a large amount of fats like this lately in our evolutionary history, our bodies don’t process them well and they lead to not only higher bad cholesterol levels, but also lower good cholesterol levels. A classic double-whammy. Margarine contains trans fats, whereas butter (high in saturated fat, but trans-fat free) at least has the protective effect of raising good cholesterol. Good cholesterol (HDL) is so healthy that it is considered a negative risk factor for heart disease. So, when deciding between butter and margarine, use butter every time. And know that the right amount of trans fat to be eating on a daily basis is none.
One final way to conceptualize a good versus a bad fat is to visualize it at room temperature. If you see a liquid, good. If you see a solid, bad. Margarine and butter at room temperature? Solid. Beef and pork fat? Solid. Cheese? Solid. Exceptions include cream, which is liquid, but high in saturated fat, and the avocado, which is solid at room temperature but contains mostly unsaturated fats and is considered a healthy fat source. The higher amount of saturated fat in the aforementioned foods gives them a more rigid molecular structure, so they stay solid at room temperature. But vegetable oils like olive oil and canola oil are liquid at room temperature. Basically, they don’t have all that saturated fat holding them up. And with a diet rich in good fats, now neither will you.
Article Courtesy: Andrew Steingrube
Andrew, while I appreciate your article in that it says fish far is good and that butter is better for you than margarine, I feel like you missed some very important facts about lipids. Coconut oil is not even mentioned. It is solid at room temperature, but does NOT oxidize at high temp cooking (ie. Frying) like all the vegetable oils you listed. It is the only oil I use for cooking. You also failed to mention olive oil. While it should not be used at high temperatures, it is a healthy oil. I suggest you look into the research on coconut oil and you'll also throw out all those vegetable oils as I did, and do your readers a better service. Vegetable oils=oxidation and omega 6s=inflammation and disease.