According to the report was published Thursday in the New England Journal of Medicine, the researchers analysed various food items like McDonald's chicken nuggets, KFC hot wings, french fries from both companies, in many countries between 2004 and 2005, the Associated Press reported.
In McDonald's in New York City, a large fries and chicken nuggets combo contained 10.2 grams of trans fats, compared with about 3 grams in the Czech Republic, Russian and Spain, and 0.33 grams in Denmark. While a large order of KFC hot wings and fries in New York had 5.5 grams of trans fats, compared with 19 grams of trans fats in Poland and Hungary, and less than a gram in Denmark, Germany and Russia.
Surprisingly there were major differences even within the U.S, where in a large order of french fries at a New York City McDonald's contained 30 percent more trans fats than the same item at a McDonald's in Atlanta. The researchers felt that the differences in the fat content are related to the type of frying oil used, with the trans fat being found in high concentrations in hydrogenated vegetable oil.
Research shows that on eating just five grams of trans fat a day increases the risk of heart disease by 25 percent. Trans fat raises bad cholesterol and lowers good cholesterol and eating it increases the risk of getting heart disease. Many restaurants to fry food use hydrogenated vegetable oil, which is high in trans fats. It was estimated a few years ago that trans fats prematurely killed 30,000 to 75,000 Americans a year, though there could be an improvement after some restaurants have started the use of healthier oils.