I thought I would post our experience and interpretation on this subject. I am one of those that will put my males on a maintenance diet after they reach about 900 grams. I am one that falls in the group that likes to keep my males in the 800 - 1000 gram range. With that said, I feed my adult males every three weeks. If they get over 1000 grams, I do not adjust their diet to get them back down, I just continue to feed every three weeks. With that said, I have a Spider and Albino male that are 5 and 6 years old respectively. The Spider is about 700 grams and the Albino is about 1400 grams. They are offered food like everyone else, but they only eat about 4 rats per year.
I quote steve above, because I don't see how this can be considered cruel. I do not mean that if someone intentially "starves" (read as offers food 2 or 3 times a year) that it is not cruel. However, we feed ours a "maintenance" diet, and they seem to thrive and do a great job during breeding season. In the wild, there is no owner there dropping a rodent in the snake den every 7 days. They may go a month or more without a meal, and seem to thrive just fine. Many adult animals brought in from the wild do not look anywhere near as full and robust as a captive animal. They definitely look more "lean" and sometimes downright skinny.
To each his own, but I thought I would share how we do it,