What should I do to lose weight?

Im a 14 year old boy.I am having trouble losing weight.I weigh 160 pounds everything I try to do is not working.I go to karate.sometimes I worry if I have problems wit my body cause im not losing anything.I walked around for about half an hour to an hour. Oh I also had this question do you nessesarily have to sweat to lose weight.what kind of workouts should I do.I usually do around 15-20 push ups,200 lifts of a 40 pound barbell,and 20 sit ups.I thought this was enough to lose weight.if you have any ideas please share.oh last question what should I eat

Don't fell bad because I tried myself it just take some time. And also try not to take the last bite but it will take some time.
By symone

Try running and doing more cardiovascular workouts, there's not doubt that you will lose weight. It also helps to eat right, stay away from candy and all other junk food.

loosing weight is more than just excersizing. even though im like addicted to it, but you have to eat right like what tyler said. and ya trying running more and increase your reps