Maybe. The most important factor isn't calories, it's metabolism of the food you eat. If you change your diet to one where you metabolize food efficiently and exercise a proper amount you should lose weight barring some physiological problem that might prevent this. For example, white flour bread metabolizes quickly into sugar and if not burned off quickly will store as fat. An equal calorie amount of oily wild fish will metabolize more slowly and therefore give you more time to burn it off. So it's a combination of calories and the more important question of what you eat. But generally, eating less and exercising more is still how most lose weight. It's just not the complete story.