What does it take for a teen to lose weight within the weeks?

i have a friend who weigh 68kg and is 165cm. she's now aged 16 and since your still 14 you can grow a few more centimetres. Of course you will have to lose some of your weigh so that it doesnt look so bad. Uhmm.. stop eating fried food & junk food. You can eat fruits but not mixing salad into the fruit dishes. Don't take a full container of crackers but take a few pieces instead. Try searching through the internet, they will tell you lots of losing weight. & no, no more yogurt or food that contains high calories. it doesnt even help with burning your calories. Run a lot, you have to. I lost 1kg by just running for 30mins. And but a scale, scale yourself every day, when you weigh heavier, don't eat too much.