There are actually no good side effects that can be achieved by malnutrition. While some people may say that malnutrition can make them lose weight, this is not exactly a good thing as the body is being deprived of what it should get. Malnutrition can cause the muscles to become soft which can make a person feel generally weaker.
The body will also not offer enough protection especially when the weather is cold. Some feel that their sex drive is not as good as it used to be anymore. They may find it hard to perform whenever they have to. Some will also have trouble in being fertile because the body does not get the proper nutrients it needs.