The antonyms for "carried a heavy load" would be to "carry a light load" or to "carry nothing at all." Instead of struggling with a heavy burden, you could easily carry a small and manageable load, or simply not carry anything and travel lightly. Carrying a light load would relieve the physical strain and enable you to move faster and with more ease. Furthermore, not carrying anything at all could free you to enjoy your surroundings, take in the sights, and enjoy your journey without being weighed down by unnecessary baggage. Ultimately, the antonyms for "carried a heavy load" offer a chance to move more efficiently and with greater comfort.