I'm sorry to read your parents didn't let you eat enough. A child should eat healthy, but be allowed to eat till their full.
I was severely underweight during much of my childhood and young adult life. I weight only 118 lbs just a few years ago. I had a very fast metabolism and without realizing it I was also under eating. Sometimes I would sit down to eat and would just lose my appetite. I got made fun of a lot because I was so skinny.
It really comes down to the fact that I wasn't fed enough as a child and that my parents never pushed me to sit at the table and eat. I was a very picky eater and was fine skipping a meal if I didn't like it. I drank a lot of soda and ate a lot of junk food which also spoiled my appetite. My mom's cooking (bless her heart) was also kind of bland.
Anyway I'm fine now and can really put the food away :)