Waist-training devices

The next evolution of corseting is trending all over social media. Waist training promises to shrink unwanted belly fat permanently.

These waist-training devices claim to give you a slimmer midsection for around $100. Celebrity endorsements are giving the corseting craze a major boost. But critics in medicine and fitness say this trend is probably too good to be true.

Miami native Nakeitha Felder is better known as Premadonna, the creator of whatsawaist.com and the Kardashian sisters' favorite waist shapers. She says she eats what she wants and doesn't exercise but the waist trainer keeps her stomach toned and flat.

Many doctors are skeptical of corseting's mystifying results. Lenox hill internist Dr. Len Horowitz says that a corset only appears to make your waist smaller. He also warns that extended use can be unhealthy because compression can interfere with digestion.

But Premadonna rejects any such criticism from the medical community.

Dr. Horowitz says to lose weight you have to eat a healthy diet and work out and strengthen your core.

For that we turn to Culture Gym founder Larry Twohig, who showed us several core exercises.