Why do people still believe in waist trainers? They do not help in any way, there are numerous articles and hard research about this. All it is is a corset to give you a slimmer waist WHILE wearing it. Once it's off, your shape goes back to normal and you will have a weakened core, not strengthened one. Also, your shape depends a lot of your genetics (and age) - outside of diet/exercise and/or plastic surgery, there's really little you can do about it. (don't mean to be a downer, just keeping it real).