Trans facts and figures
Thousands of pages of scientific research backed up the New York Health Board's unanimous decision to ban trans fats. Ultimately, though, it came down to one statistic: an estimated 1,400 New Yorkers die every year from heart attacks that stem directly from eating trans fats.
What are trans fats?
Trans fats, or trans fatty acids to give them their proper name, come from adding hydrogen molecules to vegetable oil through a process called hydrogenation. The extra hydrogen makes the oil more solid, and therefore more hardy and likely to preserve. This toughening texture also makes the food appear less greasy and therefore, ironically, gives the food a healthier look.
Why are they bad for you?
Trans fats are considered dangerous because they raise "bad" cholesterol, known as low-density lipoprotein, while lowering "good" cholesterol, known as high-density lipoprotein. The low-density version is considered bad because it transports cholesterol throughout the body, which then builds up on artery walls, making the arteries hard and narrow. In contrast, high-density lipoprotein bonds with excess cholesterol and takes it to the liver where it is broken down.
What are they found in?
Foods high in trans fats include biscuits, cakes, chips, doughnuts and some margarines.
Since January, manufacturers have had to list trans fats on ingredient labels before selling in the US, but they are often labelled as "partially hydrogenated vegetable oil".
Who else has banned trans fats?
In 2003, Denmark became the first country to effectively ban partially hydrogenated oils by only permitting very low levels, which doesn't affect meat and dairy products where trans fats occur naturally.
In 2004, restaurants in Tiburon, a town of 9,000 just north of San Francisco, were first to voluntarily give up the oils. Since 2005, Canada has required food manufacturers to list the amount of trans fat in the nutritional analysis on labels, including those from animal sources.