What many don't realise is that fats are essential for good health. The brain, for instance, is contains fat, but it is the good one and not that which can kill you. As people age they become more susceptible to weight gain and the large stomachs seen in many. The fat around their middle is from bad fats that usually come from things like sugar and trans fats.
Alcohol is the same as sugar in its molecular component. In other words, sugar breaks down into the same structure as alcohol and this is why beer drinkers end up with what is described as a 'beer gut'. But that is not trans fat but the product of a normal digestive function whereby the 'sugar' overloads the liver and turns into fat.
In that case one may end up with a fatty liver and possibly pancreas leading to cancer of the organs. It also leads to diabetes and loss of limbs, eye-sight, and heart disease, among other things.
Then there are the trans-fats and these are normal fats that have undergone transformation due to heat. They take on extra molecules of hydrogen during the process and that makes them virtually indigestible by the liver so that they are laid around the vital organs.
The worst practice comes from super heated and oft heated oils. They are found in commercial ovens where deep fried fish and vegetables are produced. They are the in many of the snack foods people are addicted to while the warning that should accompany them is that they can lead to diseases, as described above, and even death.