Jessica Simpson successfully — and famously — lost the 50 lbs. she gained with each of her back-to-back pregnancies with major nutrition and exercise changes, and four years later she still sticks to that healthy lifestyle.
The singer and fashion designer, 37, was “so committed” to losing weight after her pregnancies, her former coach, Liz Josefsberg, tells PEOPLE, that Simpson has now “changed at a cellular level.”
Josefsberg, author of Target 100: The World’s Simplest Weight-Loss Journey in 6 Easy Steps, worked with Simpson through Weight Watchers.
“I started working with Jessica right after the birth of her first child. She was hoping to lose 50 or 60 lbs., and we got down 50, and then she got pregnant,” the New York-based Josefsberg says. “I’ll never forget that phone call from her. She was thrilled to be pregnant again but she was like, ‘Oh my god!’ ”
“We sat down and designated five healthy meals that she could plan to make throughout the week, and put in her treats,” Josefsberg says. “You want to have a little flexibility in your plan. If she’s going out on Saturday night and wants dessert and a glass of wine, knowing that she can and planning that out was really important to her.”
RELATED VIDEO: Jessica Simpson Reveals She Has an IUD and Won’t be Having Any More Kids, Thank You Very Much
It helped, too, that Simpson was determined to revamp her body.
“She really wanted to get this weight off. She didn’t feel like herself for so long with these two pregnancies that the motivation was really high for her,” Josefsberg says. “I wish that every one of my clients would be like Jessica, because she would say, ‘Whatever you want me to do, I’ll do it.’ ”
Josefsberg, who also worked with Jennifer Hudson, says that these days weight maintenance is just part of Simpson’s lifestyle.
“I don’t work with her anymore because she’s pretty much got this thing. That’s my bragging point: If you look at Jennifer or Jessica, they have not gained the weight back,” Josefsberg says. “They’ve changed at a cellular level. They understand now what they need to do and they do it consistently; it’s just habitual in their lives.”
And Josefsberg was thrilled to see Simpson’s Instagram post about getting in her 12,000 steps a day just last week.
“That ended up being the perfect number for her,” Josefsberg says. “If she could get that each day she would have reduced stress, she kept her body moving, she kept her metabolism moving, and she’s still doing it to this day. When she started she was doing around 4,000 steps a day. We got her up and running.”