I think the assumption with trying to be healthy and track your calories is you are eating a healthy and balanced diet, and not things like potato chips, candy, or gasoline all day. Then with healthier food choices a consistent value for you in your life, you don't have to worry about that Starbucks drink that's 600 calories because you just wouldn't be drinking those things with this new mindset. Then it doesn't even matter your metabolic rate either; if your diet is consistently healthy and you are measuring calories and your weight on the scale, then you can dial back caloric intake and see results on that scale.