Since first cloned and reported by Zhang et al in 1994 (Nature 372:425), the obese gene and its product-leptin has been studied profoundly. Our knowledge in body weight regulation and the role played by leptin has increased substantially. Leptin serves as an adiposity signal to inform the brain of the adipose tissue mass in a negative feedback loop regulating food intake and energy expenditure. Many articles have reported weight loss at high altitude, but the explanation has been limited to loss of appetite. New ideas were highlighted after studies by Grosfeld et al and Ambrosini et al on the obese gene under hypoxia condition. Cells with hypoxia treatment upregulated obese gene transcription and suggested that enhancement of leptin secretion in vivo under hypoxia environment may be one of the potential therapeutic methods for obesity treatment.