Whether or not oils such palm, canola, rape or soyabean are unhealthy is a matter of sometimes furious debate. But evidence is piling up that eating processed food and snacks – which invariably are made using such seed oils – is almost certainly unhealthy, as is reusing oil that has already deep-fried food, a common practice in homes and restaurants. A team of scientists in India and the US carried out tests on rats and found that animals given food cooked in reheated sesame or sunflower oil “showed increased oxidative stress and inflammation in the liver” as well as “significant damage in the…