British newspapers are reporting that the duchess uses hypnotherapy to quell her lingering morning sickness and calm her aversion to food.

Many mums-to-be have the opposite problem, according to Dr. Jennifer Ashton, ABC News' senior medical contributor and practicing OB-GYN.

"A lot of women use pregnancy as a license to eat whatever they want whenever they want, but that can come back to haunt them later on," Ashton said. "What you indulge in now, you will pay for later."

Ashton advised that at this stage of the game - middle of the second trimester - "eating for two" means taking in no more than 300 extra calories per day. That's equivalent to one iced white chocolate mocha, if like Middleton, you prefer to get your extra calories in a Starbucks splurge.