Fat grams seem to work for a lot of folks, but you should also keep track of calories. (Read the remaining questions in the Overweight topic.) Next, take the total calories you eat per day and multiply by 30% to determine the number of calories from fat. (If you ate 1200 calories per day times 30% equals 360 fat calories.) Lastly, divide by 9 calories per gram to get the fat gram total for a day. (Divide 360 calories by 9 to get 40 fat grams.)
The only problem with this is it does not take into consideration vitamin and mineral content which calorie or fat gram content cannot determine.