Updated

Hollywood stars from Mariah Carey to Jessica Simpson have scored multi-million dollar deals to promote Weight Watchers, Jenny Craig and other weight loss products as the best way to shed pregnancy pounds immediately after giving birth.

So what kind of message does this send to new moms torn between focusing on caring for their newborns and squeezing back into their skinny jeans?

Nutritionist and founder of LiveNaturalLiveWell.com Heather Lounsbury says Hollywood-endorsed post-pregnancy weight loss regimes can be detrimental to both new moms and their newborn babies, because they add unnecessary stress at an already stressful time.

“Having a baby is overwhelming, exhilarating and exhausting. Stress from fatigue or worrying too much about weight loss releases stress hormones, which also go into the breast milk,” she said. “This will affect your baby’s emotional and physical health and can even cause you to gain weight.”

“[These celebrities] take the focus off healthy living, which is the most effective strategy for long-term fat loss, not just short-term weight loss,” said integrative health professional Dr. Alan Christianson, adding that with a simple healthy diet and exercise, the weight should drop off naturally.

More On This...

“If it doesn’t, women should get thoroughly screened for thyroid disease before putting lots of time and money in elaborate weight loss attempts,” he cautioned.

PHOTOS: New mom Jessica Simpson.

But scoring a slim-down deal may be hard for a celeb to pass up. Simpson, who gave birth to daughter Maxwell in May and scored a $3 million deal as the new Weight Watchers spokesmom soon after. But the stress of her new gig may have already set in, as the still-round new mom was recently forced to deny speculation that she was under serious pressure to meet her 50-pound weight loss goal.

Several other celeb moms inked deals to promote weight loss programs and subsequently showed off their super skinny post-baby bods. Simpson's Weight Watchers predecessor Jennifer Hudson slimmed down from a size 16 to a 6 after giving birth to her son in 2009. (And kept it off!) Jenny Craig brand ambassador Mariah Carey posed in a bikini after reportedly losing 30 pounds six months after the birth of her twins, while NutriSystem spokesperson Tori Spelling claimed to have lost 40 pounds after having her first child.

Not only may such emphasis on rapid weight loss be misplaced, celebs often have an army of helpers working to make sure they drop the pounds, experts say.

According to Los Angeles-based therapist Dr. Nancy Irwin, celebrities generally have an army of consultants (personal fitness trainers, chefs etc.) who sign non-disclosure agreements, thus we have no way of knowing if they do have extra help to shed the baby pounds more quickly than the average woman who uses the same program.

“These programs are excellent, but consumers should be aware that many times the ‘after’ effects are retouched,” she said. “And of course all this marketing does add pressure to a new mother to look ‘perfect’ which really raises the bar for average women without access to all these resources, or the time.”

On the flipside, Santa Monica-based surgeon Dr. Carson Liu argued that seeing celebrities endure the struggle of shedding those post-pregnancy pounds is actually encouraging to “average” moms that they aren’t alone.

“Everyone will relate to this as almost everyone is overweight postpartum. It’s a great marketing strategy to have celeb mothers push their weight loss products,” he said. “And how one looks is related to their health. People tend to look better when they drop the weight, and they are also healthier.”

Harvard integrative physician Dr. Sara Gottfried concurred that postpartum weight loss plays a key part in boosting a new mom’s outlook.

“When a new mom is able to reclaim her body, she can be more present for what Oprah calls the most important task in life – motherhood,” she said. “The window after a baby – I don’t see it as slim down stress, but as a window of reclaiming their body, their vitality, and their best health which best supports being a new mom.”

The weight loss companies that bring on big-named Hollywood moms tell us they are more than satisfied with their investments.

“Weight Watchers is thrilled that Jessica Simpson has chosen to join to adopt a healthier lifestyle and inspire others to do the same. Her talent, resilience, and positive outlook already make her a great role model, and by deciding to trade in yo-yo dieting for a healthier lifestyle, we know she will inspire many women to join her,” the company told us in an official statement.

Mike Amburgey, Executive Vice President and Chief Marketing Officer at NutriSystem said that the company “converts the promise celebrities represent into reality,” and that it lets others know that “you can diet like a star with the same success without paying a fortune.”

A rep for Jenny Craig referred us to a press release, which praised Carey for her 30-pound loss.

Joanna Mazewski, a contributor on the baby-centric site Babble.com, says being a celebrity mom is big business, and getting bigger.

“Jessica Alba is selling us earth and allergy-friendly diapers, Tori Spelling is teaching us how to craft with our kids and Heidi Klum is designing baby and toddler linens at department stores,” she said. “Celebrity parents want to reach out and relate to us the same way we want to relate to them. When we see Jessica drop down to her regular size, we’ll say ‘hey, she did it, we can too.’ It is worth every penny for these companies in the end.”