Acting on a findings of a task force appointed last year to study the issue, the Louisville Metro Board of Health voted unanimously Wednesday to recommend a city-wide ban on the use of artificial trans fat in food preparation.The substance, used to extend shelf life, has been linked to heart disease, high cholestrol and other health problems. The matter is now in the hands of health department director Dr. Adewale Troutman, who will make a recommendation of his own to the Louisville Metro Council for possible action. Troutman says it's likely he'll push for a total ban."The data says that we would save up to four hundred heart attacks per year in this city," he said.Some restauranteurs have complained that a trans fat ban would force them to use a more expensive substitute.The chair of the metro council's Health and Human Needs Committee said last week she's not inclined to support a ban but would listen to Troutman's arguments. No hearings have been scheduled.