'Sister, Sister' Star Tia Mowry Shows Off Her Toned Stomach After Weight Loss

06/25/2017 10:30 pm EDT

Tia Mowry is proud of her weight loss! The 38-year-old Sister, Sister star shared a photo on Instagram, pulling her T-shirt up to reveal a flat tummy.

"I've lost 20 pounds!" the mom of one wrote in the caption. "Many asked how? Diet and cooking out of my cook book."

Mowry switched up her diet and eating habits after being diagnosed with endometriosis and says she watched those symptoms, as well as other chronic symptoms like migraines, disappear. She even released a cookbook earlier this year, called Whole New You: How Real Food Transforms Your Life for a Healthier, More Gorgeous You.

The book boasts over 100 clean eating recipes as well as lighter versions of the classic comfort foods you love, like ''Buttermilk' Fried Chicken and Crispy Collard Chips.

"I wrote this book based on the concept that food can be medicine in its own way; that it can worsen or help with an existing condition. That was my experience, and I'm hoping that writing about it can help others too," she said in an interview with Buzzfeed.

Mowry learned the hard way how to transform her diet, but luckily she has some good advice for the rest of us. "I was told not to eat dairy — after I'd been eating it my whole life — and it was overwhelming," she confesses. Her advice? "Start slow. Find recipes you can identify with, then just test them out and see how they make you feel," she suggests.

Her cookbook comes hot on the heels of her successful cooking show Tia Mowry at Home, from which Mowry says she gained 10-15 pounds.

She's always been a staunch supporter of body positivity, and last March even called out a body shamer who wrote that Mowry was "getting fat" on Instagram.

"I don't normally do this, but I wanted to prove a point," she wrote, alongside a screenshot of Instagram comments. "I just posted a few days ago about embracing and uplifting others about body image. Here, @miekk_ felt the need to say I was getting fat. I took a look at your profile and I was sad to see that you WORK for YOUNG African American girls aiding in their studies. I hope this isn't what you would tell your girls? Does your BOSS know that this is how you degrade other WOMAN? [sic]"

Mowry worked with a trainer and ate healthy foods from her cookbook and now a year later has slimmed down considerably. We love how much hard work Mowry's put into her healthy diet and lifestyle.

"Everybody's different, but that's what I needed to do for me," Mowry said.

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