I agree with Clint on that it doesn't really matter what size you are along as you are healthy, I had a room mate at Uni a long time ago, carried a bit of weight on her, but always ate healthily, cooked with fresh food, exercised regularly. There is a problem in this world where someone sees an overweight person and immediately thinks "unhealthy," or "lazy". Without taking into to account of all the other possibilities.

There is no harm in wanting to better your society around you and help people lead healthier lives, if they want the help, however there is something wrong with forcing someone to accept your help, because you deem them unhealthy at just a glance. It doesn't work ultimately if people want to change it has to come from them.