To get a ballpark figure of your daily caloric needs, there are tools on the Web to calculate it, or, you could consult a dietitian or nutritionist. Either can give you an idea of what you should be aiming for. A good way to assess how many calories you need personally is to keep a food diary.
See how many you are taking in when you put on a few pounds. Pay attention to fluctuations and explanations for them (e.g. Are you exercising?) and be sure to factor it all in. What calorie count are you reaching during the times when your weight is steady? Then that is your maintenance calorie count aka your Basal Metabolic Rate. If you want to start losing, take a look at where you could make some easy cuts. If you are maintaining your weight while taking in 2,000 calories a day, shave off 100 calories at a time and see how your weight changes with each cut.
For example, you can eliminate 100 calories for each serving of cola you pass up that you would normally consume. A change here and a small sacrifice there will be a lot easier to stick with than trying to stay on a set-calorie diet week after week. The trick is to make your changes permanent, and, to keep a good calorie-cutting journey going by adding in exercise.
If you want to stop counting calories altogether, you can make lifestyle changes that will lead to weight loss, like practicing excellent portion control, cutting down on sugar and starches, eating more fiber (fruits, whole-grains and veggies) and drinking more water.
