Under 19 - you are underweight and it is not appropriate to be slimming. We would advise you to visit your doctor to find out safe and healthy ways to increase your weight.
Between 19 and 25 - you are just fine!
Over 25 - you should try to take steps to lose some fat. Your health is very important to us, and we do not believe that crash diets are helpful, either to your health or your long-term weight.
