Generally, the answer is a big NO, though it can be, if the kind and quality is bad.
Fats like trans fats and hydrogenated or partially hydrogenated vegetable oils are a no brainer. We know they are extremely unhealthy: they contribute to heart disease by lowering the good cholesterol (HDL) and increasing the bad (LDL). They also have been shown to get stored around the abdomen, the most dangerous area to store fat because when stored there it releases many different hormones into the bloodstream that can be problematic.
Too many polyunsaturated fats are not good either. Polyunsaturated fats mostly consist of Omega 6 and Omega 3 fatty acids, and while Omega 3 play an anti-inflammatory role, Omega 6 are pro-inflammatory. We need them both but in drastically different ratios than what we have been getting in our diet for many years now. In addition, Omega 6, when hydrogenated, can last for months, if not years, on the shelf, but become terribly dangerous for human health. Due to the politics of the food industry, as well as a simple fact that Omega 6 oils are cheap to produce (soybean, sunflower, cottonseed, etc.), these oils have been pushed for years until there was enough public outcry supported by research that something had to change. A healthy ratio of Omega 6: Omega 3 should be somewhere between 1:1 and 4:1. At the moment, it is between 10:1 and 15:1, and in some cases, as high as 25:1.
Nut and seed oils, which are mainly a combination of monounsaturated and polyunsaturated fats (depending on the source), are good in small quantities, as long as you don’t heat them. They are very unstable, become rancid at high temperatures, and carcinogenic free radicals are produced in the process. Like with fish or flax seed oils, they should be stored in the refrigerator.
Fats considered very healthy and beneficial for their antioxidant qualities, as well as for being heart protective, are monounsaturated fats like olive oil and avocados. Many nuts have mostly monounsaturated fats. Olive oil should not be heated to high temperatures. Avocado oil, on the other hand, is one of the most heat resistant, having one of the highest smoking points of all oils.
The most controversial of fats is saturated fat, with which we have a love-hate relationship. We love it because it’s delicious, and it enhances the flavor of just about anything. We hate it because we were told that it’s the source of all evil. So let’s look at saturated fat and its role in human evolution.
During the prehistoric times, before humans domesticated animals and introduced agriculture, which led to the incorporation of dairy and grains into the daily diet, respectively, man lived predominantly on hunted animal protein, with all the saturated fat included, and supplemented his diet with sweet fruit and berries, and, to a smaller degree, vegetables. Research shows that cardiovascular or degenerative disease, so common in our civilization, was non-existent at the time. Just recently, a new research discovered signs of heart disease in the population of ancient Egypt. Could it be the introduction of grains that was the cause? Or dairy? Or both? We don’t know just yet, but the truth is humans evolved on saturated fat and did very well on it. How else did we get here? If it had been so bad for us for thousands of years most of us probably wouldn’t be here today because Nature has its own way of eliminating what it considers unhealthy or too weak to survive. It’s called natural selection. This is an important question for everybody that demonizes saturated fat. There is actually NO conclusive research showing that saturated fat causes heart disease. The research that has been done shows only correlation but NOT causation. Again, food politics has played a huge role in spreading this misguided and twisted science. Saturated fat is extremely important for many bodily functions. It is needed in times of stress. It is needed for the production of sex hormones: testosterone, aldosterone, progesterone, pregnenolone, DHEA, estradiol and cortisol. These hormones are produced from cholesterol. When your body doesn’t get enough of a supply from the diet, it starts producing its own cholesterol and that’s one of the ways for your cholesterol to go up.
Saturated fat itself is not the evil. We all need it, though everybody in different amounts depending on your biochemical individuality. What is bad, however, are the commercial sources of this fat. And here’s the reason. The saturated fat of commercially raised meats is full of not only hormones and antibiotics, but also toxins from the less than perfect commercial feed. Nature intended animals to feed on grass, not grains and other products that are being used to fatten them up quickly. (If you ever wanted to know what’s in your meat, watch the movie “Food Inc.”) Toxins get stored in adipose tissue (fat) and if you eat it, you are getting it, too. Any toxin will act in your body as a proinflammatory agent. And inflammation is what leads to heart disease, strokes and other diseases.
Meat from organic, grass-fed animals is not only leaner (so you’re getting less fat overall), but also has a very different fatty acid profile. It actually has a pretty considerable amount of Omega 3 fatty acids as well as good amounts of CLA (conjugated linoleic acid), which helps burn body fat. A very different meat indeed.
One of the healthiest sources of saturated fat is organic, extra virgin coconut oil. For those still worried about cholesterol, it has none as it is not an animal product. It is great for eating, cooking, baking, salad dressings, you name it. It has amazing antibacterial, antiviral and antifungal and antimicrobial properties.
So…..look at the quality of the fats you’re eating and also the amounts. If you are trying to lose weight, no matter how healthy the fat, you still have to take total calories into account. For some people who are sensitive to carbohydrates and eat a primarily high protein diet, this is less of a concern, as most of them can tolerate a much higher amount of fat. But…..that’s a whole other subject.