"When I look at Instagram, I am made to think I should be at my best self
But most days, I lack consistency due to real life," the 45-year-old actress and mother-of-two wrote, before sharing a photo of herself three months ago and another photo taken this week.
"Here is me in a before pose and then 25 pounds later in the same place," she captioned the gallery. "You can tell my face is so much thinner! This takes me so much work. Diet and exercise and fighting like a lion for it! Damn you genetics! And yet thank you for all the good stuff."
She continued: "I love where I come from (JOHN ETHEL LIONEL) and whatever package it comes in. I just know that I have the control to be what I want. Even if it is hard AF!"
While Barrymore put in the hard work to lose 11kgs, she credited her trainer for helping transform her body. "At least I know there are experts I can turn to for help," she said. "I mean look at what Marnie helped me do in three months! When i have time off in 2019...I'm comin for ya! PS may I just say I want to be these ladies on the front page. You are my spirit animals and my goal posts!"
In 2016, Barrymore told James Cordon that when she first started filming Santa Clarita Diet she weighed 65 kgs (she is 5"4) and her life was "kind of falling apart."
That year, she and her then-husband, Will Kopelman, split after three years of marriage and that her weight yo-yo'd as a result. "I let myself go, 'cause when I'm doing the show, I'm a vegan and I barely eat anything...and I work out almost every day and it's so healthy and it gets you euphoric and then it's like food poisoning, you think you will never want to eat again and before you know it, you're just pigging out with the feed bag strapped to your face," Barrymore said during the Late Late Show with James Corden.
"And I'm a foodie and I love food and I travel the world for food, so I get heavy again between the show."