Who is responsible for enforcing compliance with weight and body composition standards in the Marine Corps?

Unit Commanders are responsible for enforcing compliance with weight and body composition standards in the Marine Corps. This role is essential because they have the authority to implement policies and ensure that all personnel adhere to the established regulations regarding physical appearance and fitness. Commanders are tasked with monitoring their unit's compliance and providing the necessary guidance and support to help Marines meet the standards.

While Commanding Officers and Medical Providers play roles in the overall health and readiness of the service members, the direct responsibility for enforcement lies with the Unit Commanders. They are expected to address issues related to body composition and to take corrective actions when standards are not met. Additionally, while individual Marines are expected to maintain their fitness and comply with the standards, the oversight and enforcement primarily rest with the leadership, which is why this option is the most accurate in the context of the question.