Nowadays obesity has become an important public health challenge. We need to be concerned about it because it is at least a risk factor for numerous diseases. Because of this and other reasons, many people wish to reduce their body weight and seem to exert all possible efforts. Practically, at least in my set-up, success rates to reduce body weight to a desired level are very low, despite the various efforts made. On the contrary, there are some people who want to have a higher body weight than they have so as to attain a normal body weight range. Still it is not usually easy to achieve it. Can you give tips, advice and experiences for both of these cases?