Andie Mitchell recalls the moment she first stepped on the scale with brutal clarity.
“I was 20 years old. I knew I was the biggest I’d ever been,” she tells PEOPLE. “I was wearing size 22 pants and even those were getting tight.”
But it wasn’t until she weighed herself at the local YMCA and saw she was 268 lbs. that she truly panicked.
“It was terrifying,” she says. “And not because of the number. It was what I knew was beyond 268.
“I just saw future versions of me where I was 300 lbs., 325, 350. It was sobering and I knew it was now or never.”
So she set a goal weight: 140 lbs. And a year later, she’d blasted through it, weighing in at a svelte 133 lbs.
“You imagine this finish line,” she says. “You can get through anything if you have an end in mind. And then of course, what you realize once you hit that goal and try to maintain it is that it’s never over.
“It’s the most shocking thing,” she adds. “You pin your hopes and your dreams on ‘When I’m thin, I will fill in the blank.’ You think everything will be better once you lose the weight. And it wasn’t.”
Mitchell felt more depressed than ever before. “What should have been so exciting was actually really scary for me,” she says. “I was terrified of gaining the weight back so I isolated myself. I didn’t want to become a failure.”
She couldn’t even enjoy going out to eat without feeling guilty. The lowest point came during a date with a former boyfriend.
“We went out to dinner and I immediately felt like it was going to be too many calories,” she says. “I remember I ordered meatloaf and mashed potatoes. I ate some of it and then I just started screaming at my boyfriend about how we shouldn’t have gone out to eat.
“I could see how crazy it was,” she continues. “I was so sad all the time. The days felt so long.”
So Mitchell sought help from a therapist. “I didn’t want to live my life in some sort of diet prison,” she says. “I didn t want to be scared and lonely.”
But she admits that in some ways it was easier being chubby. “I didn’t know that I’d have to encounter all of these emotions once I’d lost the weight,” she says.
Nowadays, Mitchell’s a healthy 150 lbs. – and she doesn’t have to swear off cupcakes to maintain it. She blogs about her story at Can You Stay for Dinner?, where she shares recipes and inspires other people to change their relationship with food.
Her advice to others looking to slim down? Learn what a real portion looks like.
“If you’re unfamiliar with serving sizes, I think it’s really helpful to spend a month learning what those are,” she says. “When I first started losing weight, I had no idea what a cup of grains looked like.”
And take each day one at a time. “For me having to think about losing 135 lbs. was extremely overwhelming,” Mitchell, now 29, says. “That makes it easy to say, ‘I’ll start tomorrow, I’ll start next week.’ It’s just too daunting.
“Don’t think about how hard tomorrow is or the day after that,” she adds. “Just commit to doing your absolute best in one day.”
It Was Me All Along hits shelves Tuesday.