When Oprah and Gayle met up with Mary Horn, Miraval's director of nutrition and exercise science, they braced themselves for the undeniable truth of a fitness assessment.
Watch Oprah and Gayle's session with Mary.
First, Mary checks Oprah's and Gayle's weights. Mary says that while most women get hung up on the number, they should really focus on their amount of lean body mass. Having a high lean body mass means you burn calories faster.
Next, Mary measures the percentage of fat in their bodies. Then, she measures their resting metabolism. This will determine how many calories Oprah and Gayle should eat per day to lose weight. Gayle's resting metabolism allows her to eat 1,800 calories a day, while Oprah's allows for just 1,600.
Are Oprah and Gayle physically fit? "It's a good place to start," Mary says.