Your body is extremely intelligent, it's already equipped to tell you when to eat and what to eat. With counting calories you ignore your natural satiety cues. For example: you already had all the calories for a day, you have a workout in the evening, but afterwards you don't eat anyting just because you already had all the calories for that day, even though your body tells you it need something to eat. Bare in mind that your body is not a bank (it doesn't have a system inside that will count how many calories you had ;)) and if it needs food, provide your body the food it needs. Some days we need more food, some days we need less, depends on how active, inactive we are or what are we doing in a day.
Fewer calories you consume, body burns fewer calories - if you consume more good quality calories, your body burns more calories. If you undereat on good calories and if you overeat/undereat on bad food, less calories you burn. Calorie restriction in the long term will slow down your metabolism and will not help you maintain weight/fat loss in the long term.
Do you count calories?