Kirstie Alley sits down with Dr. Oz to discuss her very public weight struggles and nothing is off-limits! She speaks candidly about everything from cocaine to body image. Learn what she sees when she looks back on her body over the years and why she regrets wearing a bikini on Oprah. Plus, get the tools that helped her turn her life around for good.

View Part 1 of Kirstie Alley: Confessions of a Yo-Yo Dieter.

Read more about the dangers of yo-yo dieting and how it damages your health.

Watch Kirstie Alley answer your questions from Facebook and Twitter in a web-exclusive video.

Watch as Dr. Oz and Kirstie Alley reveal the damage yo-yo dieting can do to your heart.

For more about Kirstie's weight loss visit

After years of trying to get pregnant, doctors told Kelsi Pierce it would be near impossible for her to conceive a child. However, Kelsi got the surprise of her life when her mom volunteered to be her surrogate — and she found out she, too, was pregnant!