This article is from the Diet FAQ, by Claudia McCreary email@example.com with numerous contributions by others.
Not a thing! You've encountered a "plateau," a normal (and temporary) pause
in weight loss. Your body has learned to adapt to your lowered caloric
intake and has slowed down your metabolism in order to conserve energy. The
solution to getting past a plateau is not to lower your caloric intake even
further, but to continue with your current eating plan, and perhaps to
increase your exercise somewhat. Reducing your food intake will only
reinforce our body's perception that it is caught in a starvation situation.
Plateaus seem to be more common in persons who have dieted repeatedly in the
past; their bodies have learned all too well to hang onto the few calories
that do come in.