Final answer:
At age 16, Benjamin Franklin became a vegetarian influenced by his readings and philosophical beliefs, which emphasized personal morality.
Step-by-step explanation:
When Benjamin Franklin was 16 years old, he became a vegetarian because he was influenced by his reading, including works by the health reformer Sylvester Graham. Franklin's adoption of vegetarianism aligned with his broader scientific, philosophical, and moral interests, which were informed by his deistic beliefs that prioritized personal morality over strict church doctrines.
Franklin, a multi-faceted figure in American history, later focused on his many community-oriented projects such as founding libraries, societies, and educational institutions.