I think no matter how a person may look whether they are fat, thin or somewhere in between, they should be happy about themselves and make the best use of their body, I may not be the fittest person but I still am happy with my body and the thought of hurting myself has not really came into my mind.
Being fit is always a plus point but it is not always the thing that makes you happy. If you like to eat alot, and it makes you feel great, then do so. You do not have to have the perfect body to feel happy.
It also is not that important to be popular because if you are popular and many people look up to you, you may have to reach expectations that are out of reach and un-attainable. And if you are not popular, you amy have less friends but closer ones.
I feel that as long as I am happy with myself and have a couple of really close friends I will be happy and not try to be something that I am not. I do not think that being the 'perfect' student it that great. You have to keep striving and being the best that you may forget about other, more important things, like family. And if I was a 'perfect' student I think that taking breaks and spending quality time with loved ones would help deal with the pressure instead of studying harder.