This is not entirely true. Just cutting down on calories will not be sufficient to get your body weight down to desired level. In fact cutting down calories will result in fatigue and other undesirable consequences. A thoughtful approach is to couple exercise with your daily routine and at the same time for your degree reduce your calorie consumption.
If you do not exercise, no matter how much calories that you cut down, there is going to be absolutely no use. You’ll never loose weight and even if you did is not going to be in a healthy way and you’re bound to bounce back to your original weight in no time.