IT'S easy to work out. Your ideal (理想的) weight depends on your height (身高). Try this simple formula (公式): (Height in centimetre - 100) x 0.9 = ideal weight. If a person weighs 20 per cent more than the ideal weight for their height, they are overweight. If they weigh over 50 per cent more, they are obese. For example, if you are 160 centimetres tall, your healthy weight should be (160-100) x 0.9= 54kg.