Fans may be buzzing over Adele's new look, but the superstar's transformation hasn't purely been a physical one.
"In the past, the stress from balancing work and being a mom was intense," a friend of the singer tells PEOPLE. "She wanted to find a way to balance things better."
A doting mom to 7-year-old son Angelo (whom she shares with ex-husband Simon Konecki), Adele committed herself to making healthier choices over the last year.
Cutting back on alcohol and following a diet and exercise regimen, "she is now in a very good place both physically and mentally," says the friend.
First showing off a trimmer look last summer while attending a concert with a pal, Adele sent fans — including a few famous ones — into a frenzy when she posted a glamorous photo of herself celebrating her 32nd birthday on May 5.
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"She quit smoking, reduced her drinking, got rid of sugar and stopped eating processed foods," her former London-based trainer Pete Geracimo — who worked with the star ahead of her 2016 and 2017 world tour — tells PEOPLE. "She made healthier food choices and is training regularly."
Like anyone else going through a fitness journey, Adele has faced ups and downs — but her signature sense of humor and penchant for profanity has remained intact.
"I got called every name under the sun by her," jokes Geracimo. "But to her credit, she always came ready and worked out hard."
Despite some negative online commentary about her weight loss, she's paying no mind to the chatter.
"She looks like a different person, but she's the same cool chick who will tell you to f— off if you try and second-guess her," says another insider. "She is happy and fulfilled."
For all the details on Adele's new life, pick up the latest issue of PEOPLE, on newsstands Friday.