For the purpose of losing weight it really doesn't matter if the calorie counts are accurate or not: consistency is what is important.
If you want to lose weight reliably, track your weight and your caloric intake consistently. If you aren't losing weight, adjust your caloric intake until you are losing weight at a steady ~1-2lb per week.
Losing weight is simple...it's not easy, but it's very simple.
edit: You also should continually track this because as you lose weight, your body uses less energy and your maintenance level goes down meaning you may need to adjust your calories down a bit to compensate.
If you want to lose weight reliably, track your weight and your caloric intake consistently. If you aren't losing weight, adjust your caloric intake until you are losing weight at a steady ~1-2lb per week.
Losing weight is simple...it's not easy, but it's very simple.
edit: You also should continually track this because as you lose weight, your body uses less energy and your maintenance level goes down meaning you may need to adjust your calories down a bit to compensate.