Comparisons and one-upmanship is a basic part of human nature I think. It's a facet of their self perception, the need to seem "better" than someone else to bolster their sense of self worth. Some competition can be healthy, it drives us to take that extra step, to improve and keep going. But so much competiveness comes from a place of negativity and is less about being competitive than dragging down our fellows.

I try to remind myself that while I don't have control over someone else's actions, I do have control over my reaction to them. I can choose whether to accept the minimisation and belittling of my achievement and let it get to me, or I can choose to see it for what it is and rise above it. I'll admit, it doesn't always work - but the majority of time I do manage to smile, congratulate them and carry on. The weird thing is that often this reaction confuses the heck out of them - they're just really not expecting it, expecting instead that I play the game.

FWIW, I think your weight loss is awesome and offer you my congratulations. And congratulations on the birth of your amazing baby too