With all the negative hype going on these days about the dangers of high-fat diet, do not confuse Omega 3 fatty acids [the good fat from vegetable oils] with Omega 6 fatty acids [the saturated fat from animals].  Omega 3 does not contribute to weight gain or other health problems. To the contrary, it actually normalizes metabolism, balances hormones, and reduces inflammation.  Actually both are good healthy fats that our bodies need, but the danger lies in an imbalanced ratio of the 2.  We only need about 5 times the amount of Omega 6 than we do Omega 3, but the typical Western diet provides at least 40 times as much. It is this gross imbalance that results in weight gain, hormone and brain chemistry imbalance, heart disease, tumors, cancer, arthritis, brain and nervous system disorders, including Multiple Sclerosis, Parkinson's disease, certain kinds of mental illness, depression, post-partum depression, bi-polar disorder, alcoholism, schizophrenia, dementia (including Alzheimer's), poor concentration and memory, attention deficit disorder, and a host a other health problems.  The healthy thing to do is cut down considerably on Omega 6 fats, and supplement the Omega 3 fats.  The Omega 6 fats to reduce in your diet are hydrogenated and partially hydrogenated, saturated animal fats [beef, lamb, pork, sheep, veal], and animal organ meats [brain, heart, kidney, liver - have no more than twice each week).  You should completely avoid trans-fatty acids fake fats, which include margarine, olestra, olean.  These fats are synthetic and pose a major health threat to all vial organs, particularly the liver which attempts to metabolize them.  Instead, use olive oil, coconut oil or grape seed oil to cook [Butter does not become toxic when heated, but because it is animal fat, it may tend to raise the level of "bad cholesterol" in the body].   Olive oil [Omega 3 and Omega 6], coconut oil and grape seed oil [Omega 3] are the only oils that do not become toxic when heated.  You may also use flax oil [Omega 3] on salads, but it becomes toxic when heated.  Due to increasing ocean pollution, the purity of the fish oil [Omega 3] is the single most important factor to consider when taking it as a supplement. It should be a high-grade Omega 3 oil that is thoroughly screened to assure no contaminants.