The American Heart Association has become the first big health lobby group to call for a specific limit on the amount of trans fat in the diet. In new guidance released on Monday [19 June 2006] the organisation says levels should be less than 1 per cent of total calories. However, Alice Lichtenstein of Tufts University, and who chairs the guidelines panel, says rather than worry about detailed calorie counts and fat amounts the public should get into the habit of cooking with healthier oils, and balancing calories consumed with those used through exercise.