Can you give me a strict diet plan for my 11 year old, she weighs about 83 kg?

Wow: Has she been properly evaluated by your pediatrician? Are there any other medical problems? Is she diabetic yet? Ask your pediatrician for a referral to a nutritionist who can help with meal planning, portion control, shopping and support. Get her interested in physical activities. There should be limited to no high caloric density or snack foods available to her.

No junk food: Simple sugars and processed carbs should be avoided or limited. This includes any flour product. The fine grind makes absorption quick, and spikes your blood sugar which increases Insulin and promotes weight gain. Good fats such as olive oil and coconut oil are fine in sensible amounts. Eat a rainbow of lots of organic vegetables and 3 oz protein with each meal 5 hours apart. No soda.