Where's the need?

Recently i have started to have very strong feel to change people's perception about me. I feel it is so odd that people comment on my physique in a negative way. I know i am on the heavier side but i am as fit as anyone could be. I cannot change my appearance drastically because i cannot lose weight easily, but still i chose to accept the way it is and be happy.
I feel so repulsive when people cant believe i can jog for 4-5 kms.. or my body is more flexible than theirs cos i have been working out since some time now.. I was having a discussion with a colleague in office about going to some place which is 3 kms away and he said "Have you ever walked that much in your life at one go?" I felt bad at that.. i mean i can jog upto that place in 15-20 minutes and he says have u even walked that much..
I Love to eat fruits, i love the freshness.. now recently i was having fruits in lunch.. not just one fruit, but half a dozen types.. I am having this lunch for some time now and i have experienced, not just its healthy and fulfilling but also keeps me energetic for the whole day.. BUT people reacted in a way i never even thought about - "Are you dieting?".. lolz.. fruits too have calories, they are natural sources of sugar.. and they fill our stomach too :)
When these people comment, it is still OK, cos they dont really know me.. but when my mom says the same thing i get so amused.. I know she wanted a very beautiful daughter ( i know i am.. :D ) and ever since i remember she thinks if i get slimmer i will get more beautiful.. If I am happy being the way i am, why stress out mentally about the way my body is built? I excesrcise regularly, do pranayam regularly, and see myself fit to fight the battle of life.. Then why do people still think i need to be better?