I'm 40 kg with 5'3 height,do you think I'm underweight? Since I was 14 years old (14 years ago), I never diet, now I proud with my secret altough many people critic my method. My secret?...Well, I always be sure I taking home foods and when I eat, I eat alone. You know why???because when we eat alone, we'll don't have an appetite,so it's avoid us to eat more than our body need. If you eat with somebody, you all will talking with each other, so you won't watch or beware of your food amount. Well, are you satified with my answer, I hope so. Good luck.