How do you lose weight?

I'm a teen, my parents have me grounded until I lose weight. I wasn't sure what section to put this question in. The thing is, I don't even know how to lose weight or even WHAT to lose. Because I don't have high body fat, and I do not have any flabby skin. I am 56kg weight and 5 foot 7 height. I never eat junk food or soda, and I normally eat twice a day. I have been the same weight and same weight for 4 years. I've been lifting weighs for around the same many of years too. What would you do? They are mad that I weigh 56kg.

Thats 123 lbs. Youre not making sense.

My parents think anything over 115 is overweight.

Your parents GROUNDED you because you're overweight? Did I misunderstood or something? That sounds like a stupid and mean motivation...

Yes they did

Well... that's almost abusing if you ask me :/ What kind of parents would punish their son because he's overweight?

I'm sorry you have to deal with this Have you tried to contact some other adult? Like a teacher?

You keep posting this and everyone keeps offering advice. Have you done anything to follow it?

If this is happening it is abuse. You need to take action immediately. Like I've mentioned before, get your school counselor involved, or talk to your teachers, get to your doctor, confide in a friend's parent, even call mobile crisis and the children's (and youth's) help hotline. There are a lot of things you can do.