I've dropped from 207 in Feb to about 189 right now (5'11") due to "employment issues" that have resulted in loads of free time being spent on the bike. Weight loss has plateau'd so I am throwing some treadmill running in 3x week also. I've been diligently counting calories using LoseIt on the Iphone (totally recommend this app) and limiting my intake to about 1500 a day, plus whatever my body feels it needs to refuel from riding. For instance, a typical 47 mile loop I do burns through about 2300 calories (according to my polar hear rate bike monitor) so I'll eat an extra 1000 to 1500 calories for a daily total of around 2500 to 3000.
Question is, how far down can you shave that caloric intake before the body starts to really "hoard" calories and you stop losing weight?