Core drivers:
• Deficit math: 3,500 kcal = 1 lb fat gone
• Sustainable pace: 400–800 kcal deficit/day
• Protein math: ≥0.8 g per lb of target weight
• Training: 3+ sessions/week to near failure
• Movement: 8,000+ steps non-negotiable
• Recovery: 7+ hrs sleep (otherwise ghrelin spikes hunger)