calories in / out is still a basic law to follow. but there are so many factors about lifestyle, genetics, hormones, and what you eat that affect how much you are burning via resting metabolism and nervous energy.
basically, for sedentary folk, make sure you get a lot of veggies, varied protein, omega 3....with a calorie defecit you will lose weight in a good way. carbs are good (at least cycling) to help keep hormones at good levels.
but with training, you have to up the carbs (especially post training). or else you won't recover, hormones go out of wack, injury, fatigue, all sorts of bad stuff.