When people say you're too skinny, take it as a compliment.

Whenever your look drastically changes, it screws with people's minds because they have a mental picture of what you should look like. It's kind of like this game... http://www.wimp.com/colorexam/

If you lose weight, people aren't being mean or putting you down by saying you're too skinny or you need to eat. If they were, then they would say you're too fat if you gain weight.

I'm 5'10" and went from being a constant 135-140 before college. When I went to college, I hit a high of 170 of pure fat in about a year. Nobody told me I was fat... only my family and real friends. Then I dropped down to 145-150, people started telling that I look good and that I was really fat before.

They don't say anything when you gain fat, but they say something when you lose weight.