Planet Fitness spends 40% revenue on labor. Life Time's health pivot doesn't scale. Nourish raised $215M but uses self-reported data. ZWISERFIT is an AI OS for physical businesses. One AI brain (Momo), four layers: • Saros — digital store partner (B2B) • Melody — 3-layer metabolic coach (B2C) • KinTwin — hardware-verified behavioral data • Zeus Protocol — insurance dynamic pricing Real studio. Dongguan, China. Open source. 5 YC tracks. Fitness is the first vertical.