We all know to steer clear of deep-fried and oily foods because the extra oil is bad for our hearts (as well as our waistlines). But this new study shows that it may be the temperature we’re cooking our food at that magnifies the problem, above and beyind the amount of oil we’re using.

“When food is heated up to a high temperature, new compounds are created, and some of them are known to be harmful to health,” said Raj Bhopal, professor of public health at the University of Edinburgh, who led the research. “This is not to do with frying. … it’s more to do with the cooking process, with the temperature.”
When foods are cooked at high temperatures, they release chemicals known as neo-formed contaminants, or NFCs. This group includes trans-fatty acids — or trans fats — that are known to increase the risk of heart disease. “When the temperature is high, (trans fats) are produced at a very high rate,” Bhopal said.
“This study shows that by heating and frying, you can change what appear to be perfectly healthy oils and make them unhealthy,” said Michael Miller, professor of cardiovascular medicine at the University of Maryland Medical Center, who was not involved in the research. By unhealthy, he means the creation of these chemical byproducts, such as trans fats.  The study hypothezies that using high temperatures, you can take healthy food and make it unehalthy by changing its chemicla composition.

“It makes sense to avoid snacks that are cooked in high-temperature oils,” said Bhopal, who himself has now switched to cooking olive oil. “Olive oil does not heat up to a very high temperature,” he said.

people can’t avoid these types of food and cooking methods at all times and, as with anything, suggest the need for moderation.
“Eating one meal is not going to do it, but it’s doing it day in, day out, on a daily basis,” Miller said.