A 12 year old male should have a caloric intake between 1800-2400 calories per day. Thus, your percentage would be based on that days specific caloric intake.
Using 2000 as a average, the 900 calorie burger would be 45% of your daily calories.
I don't think it's not possible to never know when you're hungry, however it may be hard to tell when you are hungry. To tell if you are genuinely hungry, you can check if you are angry, if your stomach is growling or if you wouldn't mind eating anything. You could also drink some water; if you can feel it in your stomach you need to eat.
Hope it helps, good luck! :)
You could create a diet and exercise regimen for yourself that would carve away the excess weight around your stomach over time, cut out a lot of sugars and carbs if you don't plan on exercising regularly.
Depending on your fat/muscle ratio and weight, doctors will recommend a surgical procedure to remove the excess fat because it is detrimental to your health.
In some countries it's common practice to ingest tape works so that no matter what you eat the worms make it difficult to gain weight, also helping you lose it, but this can be extremely dangerous and is not recommended by doctors .
True... If you know the outcomes of drinking alcohol, you may not use it.
