I was just asked by someone if I think they are too thin… That is an extremely difficult, almost impossible, question to answer. The reason being that each person has a body weight at which they are healthiest and it is hard to know what weight that is for each person.
So here is my answer:
If you can eat healthily, amounts that feel right to you (you aren’t starving or stuffing yourself) and foods that are healthy and feel healthy to you, and you stay at the weight you are at now, then I think you are at a healthy weight.
But, if by eating healthily you gain weight, then I would say you were not at a healthy weight and you will be healthier by gaining some weight.
So, if you have to cut out healthy foods from your diet and/or exercise in excessive amounts, there is something wrong.
What to if you realize that is true about yourself is a whole other story. What brings a person to eat unhealthily is complex and deep.