That's not true a year and a half ago I was three inches shorter and 45 pounds heavier. Therefore I don't fit either of your quailitys of thin people (though I am thin) I did eat, and I haven't always been thin. For me I went to a summer camp for two weeks at camp I wasn't snacking constantly, but just having the regular three meals a day so when my mom and aunt picked me up (my little cousin also went to camp) they were like "Oh my gosh, you look so good!" I had lost like 15 pounds. I loved seeing that result so I just stuck with eating three meals a day, and like an afterschool snack. Now I am 16 years old, 5 feet 3.25 inches, and 110 pounds! Yeah!!!!