everyone is different and there are so many different healthy eating plans out there it's difficult to gauge one element ie fat intake without looking at carbs/protein being consumed. I think the fat gram max is 65g a day so eating more than 20g will not have a major impact - are you trying a high fibre low fat approach?.
My understanding is that the lower the percentage of fat in individual items the better, so if you had say 2 bags of crisps at 10 fat grams each then that would be bad - but the same 20g spread out throughout the day ie 2g in a slice of bread, 1g in a yogurt, 3g in 10g of margarine etc will be much more beneficial and have much less impact than the higher fat items.
have a look at foodfocus.co.uk its a fab free site - its a bit of a task but it takes all the guesswork out of things. you just search for your food from a list, put it on your daily calorie intake and it calculates how far above or below recommended amounts you are -based on how much you tell it you are wanting to lose it will tell you how many calories you have got left or if you have gone over it also tracks your calories burned through exercise and deducts that too. Its well worth it to check you have your nutritional balance right.
hth