I am a schmuck on the interwebs who went to school for microbiology and I can say for certain that the human body does not violate the 1st law of thermodynamics. Calorie deficit = your body must free up stored energy (in fat) to have enough energy to continue breathing = weight loss. Unless your body is able to create sustainable free energy out of a vacuum or unless you have a horrible genetic disorder that breaks down your bones for energy or unless you are dead