Why energy pyramid loses energy

look, first of all you must know that according the first and second law of thermodynamics, their is no loss of energy but as we know it just can be changed from one form to another.so, the energy is not lost . then about the sharp decrease in energy between trophic levels i will tell you a simple illustration : imagine you have eaten 250 g of meat does your body make a benefit from all the meat ? or it will just take the needed quantity only ? then the food (chemical) energy is changed to kinetic energy (utilized in motion and doing activity), or to heat energy or to sound energy and so on…. and the rest is expelled out. the same in energy pyramids each organism save some energy for himself and transfer the rest for the higher energy level so between the trophic levels there is energy dissipation not loss.