For years, Nissa Graun was an extreme yo-yo dieter.
After trying her first diet at age 12, the mom from Mesa, Arizona spent years gaining and losing anywhere from 20 to 50 lbs., over and over again.
“That was a while ago, so the diets were about counting your fat grams, making sure you were eating very low fat and a lot of processed foods,” Graun, 38, tells PEOPLE for the 2018 “How We Lost 100 Lbs.” issue.
Graun would compound her improper diet with overexercising, and then question why she didn’t feel healthy.
“For years I would eat very low calories while working out six to seven days a week, for probably two hours a day,” she says. “So I would get to the point where I would restrict so much, and then I would keep restricting and feel deprived, and then I would over eat the junk food that put on the weight.”
Graun weighed around 180 lbs., but then she got pregnant with her first child in 2014, and gained 65 lbs., and developed gestational diabetes.
“I was told if I didn’t get control of my diet, it could turn into regular diabetes,” she says. “So for the six months following my pregnancy, I tried desperately to lose the weight with everything I had tried before — counting calories, over exercising — and none of it really helped me.”
Then Graun learned about a plan that was the opposite of what she was doing, one that focused on a high-fat, lower-carb diet.
“That actually worked for me, by cutting out a lot of the processed carbohydrates and adding in healthy fats like coconut oil or butter,” she says. “It actually started to move the scale, which nothing else would up until that point.”
For more on Graun and four more women who lost 100 lbs., pick up a copy of PEOPLE, on newsstands Friday.
She also started doing intermittent fasting, where she wouldn’t eat for 14 hours a day.
“I wouldn’t eat after dinner, and then I would wake up, do a fasted workout and then I wouldn’t eat my breakfast until maybe eight o’clock or nine o’clock … It really helped bring my blood sugars into a better range, and I was no longer considered diabetic.”
And though Graun was “kind of skeptical” when she started intermittent fasting, it quickly worked for her. She dropped 90 lbs. after her pregnancy, and when she got pregnant again two years later, she no longer had gestational diabetes.
Graun stuck to the same plan after her second pregnancy, with some slight adjustments — she now fasts for 16 hours a day — and is down 105 lbs.
“This is the first time that I’ve really eaten real food,” she says. “My body is getting what it’s designed to get, and it really loves that.”
These days, she tracks her progress and shares her healthy, fat-filled recipes on her Facebook and Instagram pages. And Graun, who naturally spends most of the year in shorts, T-shirts and swimsuits, thanks to Arizona’s heat, now feels good in her body.
“From season to season, I used to keep all of my bigger clothes because I always thought I would need them,” she says. “Now it feels good to just be able to maintain the same size season after season, year after year.”