Jessica Simpson had much to flaunt as she slipped into her 14-year-old jeans.

The mother of three has lost around 100lbs, and this has been a result of healthy eating and exercise.

The 40-year-old posed in front of a full-length mirror for her Instagram post to show the progress to her fans, and the old denim hanging in her closet for a long, long time, fit just fine on her legs.

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Showing off the low-rise jeans, she wrote: “I have kept these throwback True Religion jeans in my closet for 14 yrs (I’m not exaggerating!).

“I figured that since I’m in the final hours of my 30’s I’d give them another try, and hello 40, so nice to meet you,” she added.

The post blew up on her Instagram and was ‘liked’ by more than 300,000 of her fans, including mogul Kris Jenner.

Simpson weighed around 235 pounds after giving birth to her third child, Birdie Mae, in March 2019. Since then, her body has gone through a dramatic change and the new pictures only add to the evidence.

A part of the credit also goes to her personal trainer, Harley Pasternak, in LA. The trainer helped the celebrated singer by stressing the importance of getting back on her fitness regime.

On some of the most challenging workout days, Simpson had to walk around 14,000 steps as a part of her “ultimate fat-burning exercise”.

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According to E! News, Simpson’s trainer described how the weight-loss effort must have been for the actress and songwriter.

The trainer said: “It had to be more than just getting back from her baby weight, but how do I keep whatever I am doing now forever.”

“That’s why we are not a big fan of doing any extreme diet or radical forms of exercise.”

He also spoke about using a five daily behavior program to get Simpson into shape.

The process revolved around keeping a daily count of steps, getting a good seven hours of sleep every night, and making sure to do away with technology for at least one hour every day.

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The other two parts of the fitness schedule included eating three meals and two snacks daily. The meals must be rich with protein and fiber.

The last part was to do resistance workouts every other day.

The fitness regimen helped the fashion designer lose nearly 100 pounds in six months, and that’s quite impressive.

Simpson also seems to have finally understood the importance of diet, exercise and hard work when it comes to weight loss.

“Jessica used to skip meals to lose weight, but what actually works best for her is to eat healthfully and more often,” said a source according to Life and Style Magazine.

“She loves going out for date nights with [her husband] Eric [Johnson] and having cocktails, so she doesn’t like to deprive herself of that. It’s just about keeping it in moderation,” the source added.

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