Katie Piper has admitted she fell into "bad habits" while pregnant with her second child.
But following the birth of daughter Penelope last year, she "changed her life" thanks to a food, fitness and lifestyle regime she's now detailed in new book, The Healthy Happy Mum Plan.
Katie, who is also mum to four-year-old daughter Belle, wrote the book alongside entrepreneur and mum-of-four TerriAnn Nunns, after they were introduced by mutual friends and immediately clicked.
Katie revealed the impressive results of her regime on Instagram this week, showing how's now lost two stone and noticed "huge changes" in her body after giving birth to Penelope.
She told fans: "I can honestly say The Healthy Happy Mum Plan has changed my life since having Pea – on the left I was a few months post-partum and feeling sore & sleep deprived with a few extra wobbly bits."
I had picked up some bad habits whilst being pregnant and I wanted to make healthier, happier changes to my life.
Katie continued: "I truly believe there's no right or wrong way that you should look after having children, but I had picked up some bad habits whilst being pregnant and I wanted to make healthier, happier changes to my life.
"Not only have I now lost 2 stone but I've seen some huge changes in my body whilst on the plan, I feel more confident and am leading a much more balanced lifestyle, which shows both inside and out."
Fans were quick to praise Katie's achievement and also point out she will always be "beautiful" and "inspirational" regardless of appearance.
Katie and TerriAnn have said they created The Healthy Happy Mum Plan as a platform to share their own experiences, tips and tricks.
The book is described as a "light-hearted mum manual" to help mothers feel good and provide anecdotes on all aspects of motherhood from breastfeeding to sleep deprivation and embracing the body's changes.
The manual is aimed at mums of all ages with children of all ages and also includes relaxation techniques and at-home workout ideas.
There are food diaries and dietitian-approved recipes designed for the whole family to enjoy (and all tested and approved by Katie!)
The book advocates a 16:8 eating rule, which allows 1,500 calories a day to be consumed within an eight-hour window and no restrictions on food groups.
There is also one Treat Day per week allowing any treat up to 500 calories.
While Katie has lost two stone so far, TerriAnn - who created The TerriAnn 123 Plan - has shed seven stone over the course of her healthy journey.
Entrepreneur and television presenter Katie said: "TerriAnn and and I are thrilled to be sharing The Healthy Happy Mum Plan with all mums to provide a one-stop shop for all things wellbeing, fitness and food for you and your family.
"Since the birth of my second daughter, Pea, I have found TerriAnn's practical tips and advice extremely useful in maintaining a healthy, happy and balanced lifestyle, and likewise I was able to share some of my own 'hacks' with her.
Katie added: "We're so proud of The Healthy Happy Mum Plan and hope it shows mums that there are some very simple tips and tricks you can incorporate into your everyday life to stay healthy, happy and in control!"
Mums who buy the manual also have access to a Facebook community where they can chat with each other and offer advice and encouragement, while Katie, TerriAnn and other health and diet professionals will also engage with members.
Katie and TerriAnn attended a glam launch for the book in London on Tuesday morning.
While getting ready for the event, Katie shared a throwback photo of her cooking a few weeks after giving birth to daughter Penelope.
She said: "Currently getting ready for the press launch of @thehealthyhappymumplan with @terriann_nunns, and taking the time to reflect on how far I have come since this picture was taken.
"Pea was only a few weeks old and I was adjusting to life with a newborn AND a toddler, but determined to get back on track with my diet and fitness."
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Katie added: "Today I am feeling the best I have felt in a long time, not just physically but mentally too, and that’s all thanks to @thehealthyhappymumplan, so I can’t wait to celebrate the launch with everyone today."
She also said: "Thank you to all who came it was fantastic to talk diet, Health, mindfulness and tips with you all! This is the plan I have been following to not only get back in shape but to look after my mind and body, being the best version of me that I can be!"
The Healthy Happy Mum Plan by Katie Piper and TerriAnn Nunns is available for £39.99 at www.thehealthyhappymumplan.co.uk