Trans fat. What is it? Trans fat, also called trans fatty acid, is considered by many experts to be the worst kind of fat. It lowers your good cholesterol and raises your bad cholesterol. This cocktail actually increases your risk of heart disease, the leading killer of many men and women.   Do not be fooled by packaging claims even if they say 0 trans fat. In the US we are allowed to put half a gram of trans fat per serving into food and still make this claim. Half a gram may not sound like much but it all adds up. Many people end up eating more than the actual serving size at a time and consume these foods regularly so beware. So how will you know if you are consuming  trans fats? Always check the label for partially hydrogenated oil which always means trans fat. If it contains it ditch it and move onto something that is really trans fat free.