Step one: Subsist entirely on a single, low-nutrient food source.
Step two: Do nothing but eat and pass out between meals (from low energy and diminished brain activity).
Step three: 🐼
Symptoms may include: eradication of sex drive, complete impotence, loss of mobility (especially on gentle slopes & overlarge ladders), strong preference for monochromatic patterns, and inability to discern gender and/or species, etc.
I fact checked that bite force stat and yup, Giant Panda 1.30 kN vs Lion's 1.32 kN.
source: nice article quoting Bite forces and evolutionary adaptations to feeding ecology in carnivores (Ecology).