The American Heart Association recommends limiting the amount of trans fats you eat to less than 1 percent of your total daily calories. That means if you need 2,000 calories a day, no more than 20 of those calories should come from trans fats. That’s less than 2 grams of trans fats a day. Given the amount of naturally occurring trans fats you probably eat every day, this leaves virtually no room at all for industrially manufactured trans fats. (AHA)

Additional Resources:

http://www.americanheart.org/presenter.jhtml?identifier=3045792#limits_trans_fat
http://www.cspinet.org/nah/10foods_bad.html
http://www.fda.gov/food/labelingnutrition/consumerinformation/ucm109832.htm