18 Most Dramatic Celebrity Weight Loss Transformation

4 – Mariah Carey

After putting on 30 pounds during her pregnancy with twins Moroccan and Monroe, Mariah Carey felt pressure to lose the weight fast. But instead of turning to extreme measures she started following the Jenny system.

And it’s not all about looking skinny for the stunning singer. Working with Jenny and the American Heart Association, Carey wants to educate Americans about the risk of heart disease and diabetes caused by unhealthy eating and exercise habits.