Why is it so hard to lose weight?

Gunce • Head of research at Glow. Unwilling infertility expert. 2 kids after 6 IVF treatments.

I find it damn near impossible - maybe due to my PCOS. In fact, whenever I lose a few lbs, it comes back with a vengence. I hate it. And I know I am not alone. What are your stumbling blocks, if any?