There is a lot of debate about what fats are good for you and what fats are bad for you. You read about one diet that is all low fat then another which is all high fat. I did some research and this is what I found!
This the worst offender when it comes to to fat as it increases bad cholesterol. This, in turn, can lead to gunk building in your arteries which is bad for your heart. Trans fat is the byproduct of a process called hydrogenation. This process turns vegetable oils into solids.
In the UK, it's never been a big problem since it's most common in fast food - which is not as popular as it is in America. In America, it did become a problem so the FDA began strict regulation of its use.
These are fats most common in animal fat and animal products - milk, cheese, cream. It was first deemed unhealthy because it was thought that saturated fat raised cholesterol, and high cholesterol caused heart disease. The problem was all these assumptions were from animal studies, not human.
More recently, a broader look was taken at experimental data from different countries. From that, it was suggested that there is no link between heart disease and saturated fat!
Americas epidemic is most likely a factor of the fact that there is a huge obesity problem. So it's not what's eaten it is the humongous quantities that are eaten!
Unsaturated fats fall into two categories monounsaturated and polyunsaturated fats. These are thought to be the "good fats" and are in most cooking oils.
Mono-unsaturated and polyunsaturated fats are both thought to help lower cholesterol. Studies have been done to back this up but if sat fats aren't "bad" can unsaturated fats be "good"?
As I'm sure you know, omega 3 is found in fish but it is also quite common in walnuts as well as several herbs and spices. Omega three fats are the only fats that have all the evidence pointing in their favour. This is most likely because people don't tend to overeat on fish. Omega 3 fats have anti-inflammatory properties which means better blood flow. This lead to a healthier heart and brain.
Now this isn't one I'd heard of before I began research for this article. Omega 6 is the opposite of omega 3 in that it has inflammatory properties. This can lead to heart problems if eaten in excess. There is research currently being done to find the perfect balance between them. Omega 6 is found in sunflower oil, corn oil and soybean oil. Now corn oil and soybean oil are not the most commonly found but they make are often used in animal feed. So if it is all the animals eat it is probably transferring through to the people who eat the animals!
I don't think there is a magic combination of all the different fats. Omega 3 is good for you and trans fats are bad for you. All others don't make a huge difference. Just keep enjoying all different foods in moderation, don't overeat and stay clear of fast food! (Though even fast food in moderation is fine!). And if you can eat some more fish that will definitely help you out!