As you lose weight, you need to adapt to your changing body. You will lose a lot of muscle in the process which is okay! However, all that exercise you got from

As you lose weight, you need to adapt to your changing body. You will lose a lot of muscle in the process which is okay! However, all that exercise you got from just standing and walking normally will go away too. Maintaining condition will require intentional effort, otherwise you will start to see injuries. Think of it like physical therapy while recovering from an illness.