#BBCtrending: Can you train your waistline?
A trend for 'waist training' has become a regular and controversial talking point on social media sites like Instagram.
Waist training involves wearing a device made from tight material - think of a modern-day, gym-friendly version a Victorian corset - for long periods of time in the hope of changing the body. Hundreds of thousands of people have been sharing their experiences of waist trainers online, but there's also been a backlash against them.
So what are they? And could they be harmful?
Reporter: Anne-Marie Tomchak
Video journalist: Neil Meads
For more videos subscribe to BBC Trending's YouTube channel.