Weight Loss & Body Consciousness as a Vegan

I have an astounding metabolism and am naturally very thin. This is generally nice, but since going vegetarian and then more vegan, I'm like a rail! I feel healthy and energized, but the social stigma that goes along with looking like an anorexic supermodel type, along with being vegan (and people thinking vegans are unhealthy, and me appearing physically to verify their claims) makes me think I need to consider my weight some.

Is there some way to hold onto body fat and muscle? Do we even need to, if we feel healthy and happy? This journey has been a process of learning for me, so I welcome the thought that I could be be missing information (or particular nutrients) as easily as I welcome the idea that veganism might just require redefining our mental ideas about health and allowing them to be more flexible.

Socially, I feel humanity has been conditioned to accept a particular body as healthy, but as we begin to live differently, and feel differently, it seems that norm may not be correct for a new age of vegans - but this is a deep conditioning, so I still think about it a lot.

Any thoughts/ideas about this?