Four years ago, Cassie Sainsbury wrote a weight loss book.

Before the world knew her as ‘Cocaine Cassie’, Cassie Sainsbury wrote a book.

The 22-year-old compiled a health and fitness manual titled Shape Yourself In 8 Weeks when she was 18.

The 20 page weight loss book – which is available online for $60 – includes a workout plan, a meal plan and recipes.

“Don’t let people put you down, even if you don’t finish the program, don’t be sad." Image via Facebook and Booktopia.

“My name is Cassandra Sainsbury, I’m a personal trainer and nutritionist," Cassie writes at the start of the book.

"For the past year, I’ve been working on an ultimate weight loss guide, it’s been a long process of trial and error but I’ve finally put together a program that I’m 100 per cent happy with.”

In the book - which was published in 2015 - Cassie tells her readers to steer clear of caffeine, sugar, salt and alcohol and to ditch fad diets.

Throughout the book Cassie encourages her readers to keep going.

“Don’t let people put you down, even if you don’t finish the program, don’t be sad," she writes. "You made that first step and you tried, if you fall off the wagon, jump back on and give it your all."

At the end of the book the former personal trainer congratulates readers for making it to the end of the program.

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“Your [sic] finally at the end! How do you feel! I’m so proud of you for taking charge of your lifestyle!"

"Be sure to email your results to me, and remember, I’m here all the time, so any questions, comments or in need of a little encouragement and I’ll be there for you!"

Sainsbury is currently in isolation in El Buen Pastor Prison in Bogota, awaiting her trial for allegedly trying to smuggle 5.8 kilos of cocaine out of Columbia.