In terms of free radicals, deep-fried fish and chips are among the most toxic things you can possibly eat. When oils have been repeatedly heated to high temperatures the proportion of toxic free radicals becomes extremely high. A fat is saturated when there are no free spaces along its molecular chain structure for any more hydrogen atoms to attach. It is unsaturated when there are spaces available. Saturated fats are solid, such as those in animal fats and coconut oil.
Unsaturated fats are liquid.
A diet high in any fats, especially saturated fats, is known to be linked to atherosclerosis and coronary heart disease. This means every cell in the body becomes slightly oxygen-starved, which translates into low vitality, poor health and reduced mental concentration. Butter is saturated fat which is known to increase the risk of heart disease. It usually has very few additives, and these are often harmless or even beneficial things such as turmeric or carotene which are added for colour. However the added salt can mask a degree of rancidity in the butter.