Such a diet will lower your leptin level in about a week to half of normal. (lasting-weight-loss.com)
The loss of menstrual cycles in women and reduced sex drive in both men and women who reach extremely low body fat levels might also be explained by low leptin levels. (marksdailyapple.com)
You also tend to have a much larger drop in resting metabolic rate because of lower leptin levels. (completehumanperformance.com)