I am 21 years old male, height about 177 cm, and weight 58-59 kg. I eat a healthy diet (almost no processed food, cold drinks, etc.) which includes a couple of fruits a day, nuts, occasional oatmeal breakfast, and the usual home-cooked meals. I run and work out on alternate days (light to moderate) and feel very energetic and healthy. However, my parents are concerned that I am too thin (which I disagree with). Is there any *need* for me to bulk up from a health perspective? Or is this perhaps my body's equilibrium? Because my weight has hovered in this range for a couple of years now and is mostly stable.