well let's go to the gym and look around. how many fat people do you see working out day in and day out and still are fat. have you ever really met anyone who lost a lot of weight from from working out? it is very rare.
the truth is if you want to lose fat it is diet
if you want to build muscle it is lifting and sleep
and if you want to build a strong heart/endurance it is cardio
personal trainers and gyms WANT YOU TO THINK that going to the gym magically causes fat loss and it is a ruse to get you in that door and signing a contract.