A couple of different aspects to consider.
To lose weight, it is More Important that you look at your Nutrition Intake, both in Quantity and in Quality, before anything else. Some of my Recommendations are:
- Avoid Fast Food and Colas (Soft Drinks) of ANY KIND.
- Minimize Simple Carbohydrates (the ones that digest fairly quickly) such as White Rice, White Bread…
- Eat more Complex Carbohydrates (ones that do NOT digest quickly), such as Oats.
- Note that Vegetables are an EXCELLENT source of Carbohydrates and other Nutrients.
- Whole Milk is Pretty Good to drink too.
- Ensure that you eat Good Quality Protein in Adequate Quantities with each Meal.
- NEVER SKIP BREAKFAST.
- Make sure that you eat a Good Amount of Quality Protein with your Breakfast…very important.
- Dietary Fat is good to eat and will NOT make you FAT… All fat are good, except the Trans Fat kind.
- Eat only when you are hungry…eat slowly…chew your food well. Stop when you start to feel full.
- Don’t even buy Junk Food…you can’t eat what you don’t have.
- Strength Training is an EXCELLENT way to grow Strong and Healthy. They develop muscles, make you bones grow denser (stronger) and of course, overall, makes you stronger.
- Squats, Deadlifts, (Overhead) Presses, Bench Presses…along with Chin Ups are an EXCELLENT set of Exercises to Train on, for your Strength and Overall Health.
The other aspect that you should be looking into is…what kind of workouts.
You need to take it easy. Given your age and that you have many years left to grow taller and bigger, just take it easy. Ensure that you DON’T do the Exercises with Wrong Form and DO NOT overdo, in terms of lifting too much weight. You growth (how tall you will grow) will NOT be affected by Strength Training, Done Correctly.
However, if you workout with Terrible Form and / or Lift Too Much Weight than your Body is Adapted to, then, this might damage your Growth Plates and could impede how Tall you become.
Also, you might want to approach a Pediatrician to ensure where on the Tanner Scale you are at. Until you reach Tanner 4, it is best to just workout for fun. Once you have reached Tanner Stage 4, then, you could get into a Strength Training Program that has Linear Progression as its foundation.
You’ll need to approach a Qualified Professional, to Design an Appropriate Training Program, and also of course, to Train you on each of the Exercises mentioned above. Then, it is important that you stick with the Training Program.
Hope this helps!