If you tell people that the secret to losing weight is "eat less and exercise more", they a) think its too simple to work and b) too onerous to actually do.
Delta in mass = inputs to the system - outputs from the system - energy expended by the system. If you desire negative deltas, decrease inputs, increase outputs, or increase energy expended. (Options #1 and #3 are probably better for most people, owing to the inability to control #2 in a safely scalable manner.)
The human body does not get a free pass from physics just because its details are complex.
Delta in mass = inputs to the system - outputs from the system - energy expended by the system. If you desire negative deltas, decrease inputs, increase outputs, or increase energy expended. (Options #1 and #3 are probably better for most people, owing to the inability to control #2 in a safely scalable manner.)
The human body does not get a free pass from physics just because its details are complex.