"Fit as a fiddle" is a phrase that is often used to describe someone who is in good health and physical shape. However, there are several other synonyms that convey the same meaning. For example, someone who is "hale and hearty" is in good health and has a robust constitution. Another synonym that can be used is "in fine fettle," which means someone is in excellent physical condition. Similarly, "healthy as a horse" is often used to describe someone in excellent health. Finally, someone who is "full of beans" is not only physically fit but also energetic and lively. All these synonyms emphasize the importance of maintaining good health and well-being.