"I wanna tell them that we're all gonna die!" she said, in an interview which is now being widely circulated on social media.
"You're all, like we're all gonna die. And what if you're on your deathbed and you're thinking ... think about all the time you wasted worrying about that s**t."
The comedian said she doesn't think about her looks - something she considers to be "really freeing".
The blunt message has resonated with people all over the world.
"So true. Such a waste of time and energy," Katie Couric replied when Schumer shared a clip from the interview on Instagram.
"I am a 54-year-old guy who needed to hear this message as well," another Instagram user replied.
"Yes. Just turned 50 and see photos of myself in my teens, 20s, 30s, 40s ... knowing myself in those photos and the terrible things I used to tell that woman about her body. Such a waste of time and held me back from doing things. Thanks Amy!!! So appreciate your voice," someone else commented.
"Yes! I'm an oncology nurse and I've had a few younger women dying of cancer tell me they wish they never wasted so much time worrying about their size. All they wanted was to enjoy food again," another Instagram user said.