The ancient Greeks believed that medical treatments could be observed from nature, and since humans, like most animals, naturally avoid eating when they become sick, they believed fasting to be a natural remedy for illness. In fact, fasting can be considered an instinct, since all animals—dogs, cats, cattle, sheep, and also humans—avoid food when sick. Think about the last time you had the flu, or even a cold. The last thing you probably wanted to do was eat. So fasting can be considered a universal human instinct for handling multiple kinds of illnesses.
