Remember, though, that we only absorb a certain proportion of the calories available in our food. Our rules of thumb about estimating caloric needs based on basal metabolic rate are approximate and work for many people, but not all. Digestive and metabolic disturbances can result in some folks not absorbing calories and nutrition (classic presentation of celiac) or extracting calories much more efficiently. The preparation of food also influences this processing: the energy required to digest your food starts to become a non-trivial factor. If you're struggling with weight despite tracking your intake, it might be worth switching your intake to foods from which you absorb fewer calories and for which you expend more energy in digestion: nuts, raw vegetables, and less sugar etc.
http://blogs.scientificamerican.com/guest-blog/2012/08/27/th...