Again, calories are important, but nutritionists do not consider that the main consideration in weight. The main consideration is how well or poorly you digest the food you're choosing to eat and how the food you eat affects metabolism. Again, the same example I'm always posing, salmon is very high in fat and calories but won't make you fat unless you consume a ton of it. A piece of white bread, a simple carb, will turn immediately to sugar and store as fat if you don't burn it off immediately, though it's much lower in calories than a good piece of salmon. Also, people are tossing the term "carbs" around a lot these days, but not distinguishing good carbs from ones that might be problematic. Most of a healthy diet is going to be carbs, given that all vegetables are carbs. It's the carbs that quickly metabolize into sugar and store as fat that are problem, not complex carbs. And if you play basketball, which is very aerobic, you're going to need those complex carbs for energy, such as whole grains. As for insulin resistance, that makes your case much more complex and probably beyond the resources of people on a website, so you might benefit if you can afford it by seeing a holistic nutritionist or maybe one connected to sports since you play basketball and might have a good angle on one from more advanced players or your coaches. And don't think of it as following a diet, in the sense this is a temporary thing to lose weight and then you're going to go back to what got you to this point. Think of it a permanent lifestyle change. Now, you're only 13, and you're body shape isn't set yet most likely, so don't do anything too radical. Don't go on any crazes that might rob you of the varied diet you need to develop. Good luck.