It's why the medication should never be given to people on its own (although I'm sure it happens all the time), but should be a part of a comprehensive weight loss, exercise and dietary plan. Same with other invasive weight loss treatments, you can't just get a gastric belt or whatever fitted if you ask for it, you need to do the work yourself first, and you get a diet plan assigned if you do end up with one.

It's the same with e.g. human growth hormones, one theory is that Elon Musk is / has used them, but without the weight training that should go with it, so his body has developed really weirdly.