A mere six months after birthing her third daughter, Birdie Mae Johnson, Jessica Simpson emerged with a well-sculpted body just fit of a celebrity.

Although she looked very stunning, the drastic change left many fans apprehensive that the longtime entertainer has resorted to unhealthy diet schemes. However, her nutritionist says it's the exact opposite.

Celebrity nutritionist Liz Josefsberg, who also worked to help Simpson lose weight after her first two children, shares that the "key" to Simpson's weight loss after each of her pregnancies has been "moderation" and "indulging intelligently."

"During the time I worked with Jessica following the birth of her first two children, she was following Weight Watchers. She spent well over six months working off weight from her first and second pregnancies. She ate regular meals throughout the day. Usually three times and a snack," Josefsberg says.

Josefsberg further stresses that this time, Simpson managed to consume a minimum of 100 ounces of water every day. This ensured that she was fully hydrated while performing other activities to help her lose weight.

Josefsberg shares that not only did drinking so much water help Simpson tamp down on hunger pangs, it helped increase her metabolism.

Josefsberg:

"Much of the overeating we do is mistaking thirst for hunger. If we can keep our bodies, which are made up of over 60% water, hydrated, they burn calories and metabolize food at an optimal rate!"

In addition, Simpson's fitness trainer, Harley Pasternak, says that aside from her regular gym sessions, the gorgeous entertainer managed to stay active by taking at least 10,000 steps per day while monitoring with a pedometer.

It may seem extreme, but the results are more than worth it!