The thing is, when you live in an unhealthy manner, you won't just live with minor symptoms of it, before your body just has enough and dies immediately. You will have to face the long time consequences for decades. If you decide to do so at the age of 17 or 20, and find a romantic partner later, you might see things differently by the time you notice how your health degraded.
I'm obviously not trying to get you to live healthy - you do you. But in my experience, not caring about your future self will just make it even harder when it becomes your present self - and on top of that global recession, famine, wars, diseases and whatnot now you will also have to deal with an achy foot, constant coughing or crippling depression. For a long time.