Trans fats are also known as hydrogenated fats. They are made by adding hydrogen to liquid vegetable oil under pressure. This results in a stiffer fat, a fat which is hard at room temperature. For example, vanaspati is a trans fat. They are artificial, they are man-made. All the trans fats are essentially artificial, only, very minute quantities of trans fats are found in animal meat and some dairy products.

They harm by increasing the cholesterol levels in the blood. They also increase other harmful fats in the blood. They also bring down the "good cholesterol" the helpful cholesterol, or HDL cholesterol, in the blood. That means that trans fats work both ways, in spoiling your blood fat levels, by raising the harmful lipids and bringing down the good lipids. They block the arteries and prevent blood from flowing through them.

In women, trans fats actually doubles your risk of heart disease! Trans Fats also leads to decreased cognitive function of the brain, in people more than 65 years of age.

Trans fats are also very harmful to the children. It has been shown that children as young as 8, and 9 years have high cholesterol and early stages of clogged arteries.

Trans fats are found in biscuits, breads, confectionaries, fast-foods, fried food items, including namkeens, fried sweets, many cakes and pastries, ready to eat meals, fast foods, junk foods, microwave meals and snacks and much of the street, restaurant and hotel food, etc;

Many halwais, street vendors also use vanaspati instead of ghee.