I'm 6' 2" (1.88m) and weigh 154 pounds (70kg), might be skinny, but not anorexic in the least. In fact, calculate the BMI for those "anorexic" people and you'll find that they've got a healthy weight.
BMI = weight (kg) / (height (m) ^ 2) (or do it in pounds & inches and multiply by 703), healthy is between 18.5 and 25 (only for adults, and for example, if you're Asian it's between 18.5 & 23). Although if you're an athlete, it won't be correct, might be a lot more or less depending on what sport you do.