Fat and the DS

So I am wondering How much fat does one need to consume for basic bodily function?

I know that low fat diets are what most people in the world are trying to do but your body still does need some fat to function, To lubricate joints etc.

So what is the daily amount of fat that is needed to survive healthly?

As a DS'er I am trying to find my "sweet spot" for fat/carb/protien ratios and i just want to make sure that i am getting enough fat into my body to not do it long term damge since i malabsorb most of the fat that i eat.

thanks
catnip