My brother is way worse with food than I am, but I'll admit that I eat too many pre-packaged, processed foods, etc. I'm 12, 6 feet and 220-230 so it isn't that bad... My brother is 18, 6 feet 2 inches tall and 350-400. My current BMI is between 29 and 31. I want to get it down to 20-25. My brother's BMI is between 45 and 51.
To calculate your BMI take your weight multiplied by 703, divided by your height (in inches), and then divide again by your height (in inches)...