1. Realize You’re Still Growing

If you’re wondering how to lose weight fast, and you’re still in your teens, keep in mind that you’re still growing! During your teen years, you’ll just naturally gain and lose weight as your body adjusts to hormone levels and as your body develops its own metabolism. Don’t panic every time you gain a pound or two… you’re still growing!

2. Play Sports

When I was a teenager, I kept fit by running on the cross-country team. If you’re at all interested in any team or individual sports, try out or sign up! Sports are a marvelous way to make and keep like-minded friends, and to stay fit (or lose weight).

3. Choose One, Swap the Rest

My teen years were a haze of chips, soda, and candy - I lived in a junk food heaven. But that’s terribly unhealthy, and unfortunately, still a part of most teens’ lives. Am I suggesting that you stop eating junk food. No. But it would be a great way to start living a healthier lifestyle to choose one vice, and swap the rest for something much healthier. For instance, you can keep eating movie popcorn at the movies, but skip the soda and choose bottled water. Or, feel free to have chips with your sandwich at lunch, but skip the soda and have a piece of fresh fruit or a crunchy vegetable instead.

4. Skip the Soda

Did you notice I mentioned skipping soda TWICE in my tip above? That’s because it’s one simple way for teens to lose weight fast. Each serving of soda contains loads of empty calories. Over time, those calories add up to pounds. Skip the soda altogether, or at least switch to diet or zero-calorie.

5. Do It NOW

If you’re a teenager who’s struggling with serious weight issues, don’t put off weight loss. It will never be easier than now. I’m not saying it will be EASY, just EASIER, to lose weight in your teens, than say, in your 40s.

6. Find a Friend but Ditch the Frenemies

Your friends can make or break a weight loss goal. The right friends will support and encourage you. Frenemies will break you down and sabotage your healthy efforts. So stick with the friends you know you can count on, and ditch the mean girls.

7. Turn off the TV and Computer

We spend more and more time doing sedentary things (on our butts!) than ever - watching TV, playing video games, using the computer, or even just sitting and texting friends. This is terrible! Not only does it hurt our actual real-life relationships, it discourages the physical activity we all need to lose weight, and keep it off. If you want to lose weight, or just be more fit, shut off the TV and walk away from the computer.

8. Get up and Dance!

Let’s chat more about video games. I do have a soft spot for any game that encourages physical activity, like the dance games. They’re so much fun, and some are even very good exercise! These video games are an excellent way for teens to lose weight, or just be fitter.

9. Do It for YOU

If you’re thinking of losing weight because you think that’s what your friends want, or your parents, or your boyfriend, or anyone else for that matter, stop and take a long hard look at yourself. If YOU like what you see, or are confused by the messages you’re getting from peers or relatives or the media, go see your doctor for a truly objective opinion. He or she will tell you, honestly, if you need to lose weight, or if you’re being influenced by someone, or something, else. Do it for you!

10. Ask for Help

It’s hard to be an overweight teen. You get bullied and laughed at. No one wants to help, they all just want to make fun! If you’re feeling bullied, threatened, or just overwhelmed, ask for help. Ask a teacher, a relative, a friend. Don’t try to take on the world, or a weight problem, all on your own.

11. Start Slow

Losing weight is never going to be the easiest thing you've ever done. Instead of jumping into it and making a million changes all at one time, start slow and build on your momentum. Maybe you cut out soda during week one, then add a new fruit each day during week two, then add one new exercise activity during the third week. The trick is keeping up with each thing and adding to your new habits as you go. As time goes by, you'll start seeing progress and the small changes you're making will add up without being so hard.

12. Pack Your Lunch

Sure, eating in the school cafeteria is easy and effortless, but let's be honest. Not all of the selections are good ones, especially if your school offers a la carte options. Instead of being stuck choosing between a cheesy burrito or a fat-filled, greasy burger, pack your food at home and bring it with you. That way you can control how much and what you eat and lunchtime so you can keep calories in check. Try string cheese, almonds and an orange or apples and celery with peanut butter, paired with low-fat yogurt. Each option is nutritious, filling and low in calories.

13. Snack between Meals

This might sound counterproductive, but hear me out. When you go too long without eating, your inhibitions tend to fly out the window and you make terrible choices because you're so hungry. You know - when you binge on 5 tacos at lunchtime because you haven't eaten since you got up many hours ago. Aim to refuel your body every couple of hours with a healthy, low-calorie snack so you aren't as tempted to eat everything in sight.

14. Sleep More

When you don't get enough shut-eye, your body has a hard time controlling the hormones that drive appetite. In other words, if you sleep for too few hours, your appetite is going to be in overdrive, which will only mean eating more than you need to. Try to get enough sleep each night so that you can resist junk food and make healthy eating choices all day long.

15. Don't Skip Meals

You might think that skipping meals will save you calories, but the truth is pretty much the opposite. Much like the advice above regarding snacking, you need to have a substantial meal at least every 4 hours or so to keep your hunger satisfied. If you let yourself get too hungry, you set yourself up for a binge that is never going to help you lose weight. Bottom line - eat something at every meal!

16. Measure Your Portions

It can be very hard to determine if you are eating the proper portion sizes. Until you can easily eyeball a serving, it's a good idea to weigh and measure your foods. Use a basic kitchen scale and measuring cups to get an idea of what makes up a portion. Chances are yours have been too big (most teens eat huge servings), and cutting back will be an effortless way to eliminate calories from your meal plan.

17. Exercise

If you play sports, chances are that between practice and games, you are getting plenty of cardio. If not, you should be aiming to get 30 minutes of physical activity each day. Running, swimming, skateboarding and biking are fun options. When you exercise, you burn calories, which can aid in weight loss as well as keeping your body healthy. You should also be strength training a couple of times each week, which builds muscle and boosts metabolism. Lifting weights is a great activity for any teen girl.

All of these tips are proven, tried and true, all excellent ways of how to lose weight fast for teenage girls. Remember that first one in particular - it’s so true! So find a friend to help you along, and get going, sweetie! Which of these tips do you think will help you most? Or do you have another tip that will help teenage girls lose weight? Do tell!

This article was written in collaboration with editor Eliza Martinez.