As far as I know, the fats in food, do not amount to body fat, body fat is caused by carbs which turn in to sugars in the body causing the body to produce insulin. Insulin is what turns in to fat. So if weight loss is the main short term aim then it's the carbs and sugars that need to be cut, so try and stick to berries and nut's for the short term. Also I read somewhere that the fats in Nuts, Avocado's,olives, Meat, Fish etc help the body obsorb vitamins/ vitamin, I can't remember which one?
The fats that do harm are the trans fats or hydrogenated etc the sort of thing that chips/fries get cooked in.
I am certainly no expert, so if I've put anything that isn't accurate then someone please point it out. I have also used the Atkins diet, which proved to me that eating fats does not make you put weight on, and after eating bacon and eggs in the morning, meat and salad at lunch time then big steaks with veg at dinner time, I would wonder how it was working, so for me, it's cutting the bread,pasta,potatoes etc that worked.
What I prefer about this way, is it's not a diet, it's a lifestyle (and a very easy one to follow) and you can have fruit with it, which I really missed when I was on the Atkins. Also there's no gimmicks with this, everything can be bought in your local green grocers, butchers,fishmongers without added supplements designed to keep you hooked.
Anyway, rambled on for far to long but I hope this helps.

Iain