Well for one, weight loss isn’t a linear event over time. When you cut calories, you may drop a pound or so each week for the first few weeks, for example, and then something changes. You eat the same number of calories but you lose less weight. And then the next week you don’t lose anything at all. That’s because when you lose weight you’re losing water and lean tissue as well as fat, your metabolism slows, and your body changes in other ways. So, in order to continue dropping weight each week, you’ll need to continue cutting calories.