Since cuisine is based on taste, the best or worst cuisine in the world is a relative term. A dish considered a delicacy in one culture will be considered horribly disgusting in another culture. Many cuisines in Africa and Asia include animals that are not on the menus of Western restaurants. These include organisms such as monkeys, grasshoppers, and other animals that do not usually occur in Western countries.
Because of globalization, certain cuisines are more common than others, such as Chinese, Indian, European, Middle Eastern, and American cuisines among many others. Less popular culinary traditions tend to be considered unusual and less popular. However, it is just an accident of history and economics that these became the less usual or popular foods and it might have been the other way around if history was a little different. As a result, there really is no objective answer to the question of what cuisine is the worst, at least in terms of taste.