The best option for cooking is saturated fats, like coconut oil, butter or lard. These fats can stand a lot of heat without transforming into poison.
More on the dangers of heated vegetables
Note that these oils are another example of vegetables/plants turning into cancer-causing substances when overheated. The most cancer-causing substance on earth is also a plant:
This is not an attack on vegetables, or a way of saying that meat is better. It’s just a fact that both processed meat (like bacon) and processed plants (like oils, or tobacco leaves) contain cancer-causing substances when they have been overheated.
Don’t use excessive heat when cooking. Make sure the food you cook can handle the heat.