Every time you lift weights, your body starts rebuilding itself stronger. When you train, your muscles get tiny micro-tears in the fibers. That’s actually good—it’s the first step to getting stronger. After your workout, your body repairs those fibers using protein and rebuilds them bigger and stronger. This is called muscle hypertrophy. The more muscle you build, the more calories your body burns—even at rest. So lifting weights doesn’t just build muscle, it also boosts your metabolism.