Like the title says, my sister has anorexia which has been an ongoing issue now since 2011. She has had help in the past but relapsed soon after. We have always been really close but I feel this will drive our relationship apart sooner or later. I dread going to family dinners and watching her sit there with an empty plate, followed by hours at the gym doing cardio. Everytime I voice my concerns she shuts me out and tells me not to worry and that I make it worse by interfering. I know people say you can't help those who don't want to change but surely there's something... Whether it be small or big that can help?? Is it time I leave her be or do I continue to try?

Tl;dr: Sister has anorexia and its driving our relationship apart. Not sure whether to continue trying to help or leave her be?