Know your sources of trans fat. Since 2006, the FDA has required food manufacturers to list reportable amounts of trans fat on the Nutrition Facts label. What's considered reportable? Food manufacturers don't have to report the trans-fat content if it's less than 0.5 gram per serving. So check the ingredients list for hydrogenated or partially hydrogenated vegetable oils even if the Nutrition Facts label reports 0 grams of trans fat.