no. being malnourished can apply to anyone. malnourished means “suffering from malnutrition.” an average weight or over weight person can experience this. when you are malnourished you will, loose your appetite, wounds will take longer to heal, get cold easy, get ill and take a while to recover, etc. in short, it’s a lack of nutrients. so you don’t necessarily have to be underweight to be malnourished.