Most people do not get quite enough (or virtually any) Omega 3 in their diet, and they get *massive* quantities of Omega 6. Both are essential, but in *very small amounts* and in a ratio of about 1:1 to 4:1 maximum of Omega 6 to Omega 3. In fact, 4:1 is probably much too high for optimum health.
We really need lots of saturated fat in our diet; it's *vital* for our health, unlike what we have been told. Polyunsaturated oils give us massive amounts of Omega 6, they oxidize in the body, we never consumed them until there was machinery available to press out the oils from seeds/grains/legumes (such as sunflower, corn, soy), so we have not evolved to be suited to eating them, and we never ate the foods from which they come until quite recently, either, and certainly not in great quantities (people did eat a few seeds, but no grains/soy as we were evolving). In addition, except in times of scarcity, as we were evolving, people ate most of the calories from animal fat and protein, discarding parts of the animal that were lean, with the innate body wisdom of those whose tastes haven't been corrupted by industrial "food".
It's even hard to get lots of saturated fat in our diet these days, as the animals we eat are mostly fed grains, which is a species inappropriate diet for them, too. That means that *especially* non-ruminant animals are loaded with PUFAs (polyunsaturated fatty acids), which are very bad for our health. At least beef and meat from other ruminants, when grain fed, can turn their fat into saturated fat. The bad thing about factory farm beef (outside of the intolerable and incredible cruelty, the antibiotics and hormones, and the sheer junk they're fed in addition to junky grains) is the fact that they have much more Omega 6 (from their diet) than Omega 3 and CLA. Our chicken, other poultry, pork, etc. are loaded with PUFAs, which cause cancer, heart disease, other diseases and premature aging, unless we can find truly pastured, rather than "free range" (which are not really free range) animals directly from farms. One has to be careful to ask if *any* grains or soy are fed, as many put their animals out on pasture and also feed grains.
I have stopped using *any* polyunsaturated vegetable oils, and make mayo out of a combination of (mostly) coconut butter warmed to 78 degrees to make it liquid, and a mostly monounsaturated oil, such as olive or almond oil. I'm still using grain fed poultry and pork, but am looking for sources to buy that type of meat from pastured animals. I do buy beef and dairy products directly from farms that graze and *grass finish* (many stores claim to have meat from grass fed beef, but they are *finished* with grains, which is what influences the composition of their fat) their cows. This way, I also know that the animals have had a good life with people who cared about their welfare.
In addition, it's best to get your Omega 3 from naturally raised animal products (or, if you can't find those at all, from Gold Circle Farm Eggs or Carlson's or another good, non-rancid brand of DHA from fish oil). If you use flax seed oil, it's bound to be rancid, even if you buy from a good producer and keep it in the freezer, and your body cannot efficiently convert ALA to EPA and DHA, which is what we need, so the ALA will build up in the body, which is *not* a good thing. So, I recommend not using flax see oil, and not depending on *farmed* fish, but getting your Omega 3 from fish oil (from wild fish) and meat and eggs from pastured animals.