My opinion will differ from others, but since I'm a fan of Atkins diet and Blood Type Diet , my personal belief is that fat intake has nothing to do with weight gain. (unless you drink galloons just to prove me wrong)
I used to believe that ridiculous food pyramid of low fat and high carbs.(invented by lawyers of all health experts) then I found out that carbs are the problem. I know eat all the fat, Sea Salt and protein I want and I'm 25 pounds lighter than when I ate a low fat diet recommended by your government.
People are probably sick of me comparing horses to humans, but when I want to fatten up my horses, I give them bread (very little fat in bread) when I want to thin them up for a race, I up their fat intake to as much as they can take or will eat.
Just my humble little opinion that works for me.