Saturated fat found in butter, meat or cream is unlikely to kill you, but margarine just might, new research suggests.

Although traditionally dieticians have advised people to cut down on animal fats, the biggest ever study has shown that it does not increase the risk of stroke, heart disease or diabetes.

However trans-fats, found in processed foods like margarine raises the risk of death by 34 per cent.

"For years everyone has been advised to cut out fats,” said study lead author Doctor Russell de Souza, an assistant professor in the Department of Clinical Epidemiology and Biostatistics, at McMaster University in Canada.

"Trans fats have no health benefits and pose a significant risk for heart disease, but the case for saturated fat is less clear.

"That said, we aren't advocating an increase of the allowance for saturated fats in dietary guidelines, as we don't see evidence that higher limits would be specifically beneficial to health."

Saturated fats come mainly from animal products, such as butter, cows' milk, meat, salmon and egg yolks, and some plant products such as chocolate and palm oils.

In contrast Trans unsaturated fats or trans fats - are mainly produced industrially from plant oils for use in margarine, snack foods and packaged baked goods.