That means purposefully eating more or fewer calories. Like one day your calorie intake is low, say 1200 calories and then the next day its high 1600 calories. Some people have a certain pattern they follow like 3 high days and 4 low days. That way it keeps your metabolism guessing instead of slowing down as it tends to do when you eat low calories all the time.
My husband and I use this to rationalize our 'cheat/treat' meal once a week. It seems to be working ok as he's lost 115 lbs and i've lost 35 so far.
Try googling calorie cycling and you will get lots of hits.
