The singer has lost one and a half stones after finishing a gruelling three-month stint in panto at the Pavilion and she wants to make sure it doesn't go back on again.
"I've just come back from a holiday in the sun and I'm feeling great, so I'm looking to capitalise on that now," she says.
"It's perfect timing because one of my new year's resolutions in January was: I'm 33-years-old, I want to get fit and healthy."
Michelle has no qualms talking about her battles to lose weight, all carried out in the public eye.
"I wake up every day thinking about getting fit and healthy and watching what I'm eating," she reveals.
"My weight fluctuates all the time, I've been 23 and a half stone, I dropped to 12 stone then I went back up to 17 stone.
"The fact the Evening Times has taken on board this campaign and is promoting a healthy lifestyle for everyone, you can't help but get behind it and be 100% in support."
The Pop Idol winner, who went on to present STV chat show The Hour with Stephen Jardine, is joining her friends for classes at her local Glasgow Life gym and vows to improve her diet.
"I've been every size but I always feel my happiest when I'm losing weight and trying to be fit and healthy," she admits, "whether it's going a walk around Pollok Park or walking up to the main street to go shopping instead of taking the car.
"For my mental health, I feel a much more positive person when I'm fit and healthy.
"There's nothing more depressing when you're trying on clothes and they don't fit and you know you've put on weight."
She believes reading about the achievements of others in the coverage of Active 2014 every week in the Evening Times will encourage her to get healthier.
Active 2014 aims to improve the health of Scots in the year of the Commonwealth Games and build a lasting legacy of physical wellbeing.
Working with partners Glasgow Life and NHS Greater Glasgow and Clyde we'll be creating exciting opportunities for individuals, communities and businesses to get active as we bid to improve the health of as many people as possible in the community.
The message of this campaign is that even the smallest of changes in activity and lifestyle can make a huge improvement in health.
"I've bought a juicer because I eat an awful lot of junk food. Every morning without fail I can now have a big vegetable juice and get my five a day.
"I'll be ditching the car and walking more. I'm lucky, I live up four flights of stairs in a tenement. Why I'm not a size eight I'll never know!"
She partly blames her weight fluctuations on the simple fact that she doesn't have a regular work schedule - every day is different.
"I might have a day off and go to the gym, another day I might have three packets of crisps and a pizza for dinner and a bottle of wine with my mates and I've not done anything.
"That's why panto was so good, it was three months of strict routine.
" I ate two or three times a day and I was burning so many calories. It shows you the potential you would have to lose weight if you were in a regular routine."
Every week in her column in the Evening Times, Michelle will be charting her achievements. She says seeing it there in black and white will be a great incentive.
"Although my life is hectic, part of it is laziness," she says. "I could be getting up first thing in the morning, going out to the gym before my day starts. I don't, I sleep though my alarm and don't bother getting up.
"It's all about small changes and they can really make a difference."
THE singer has just signed up to do panto again at the Pavilion this year and plans to take her 2013 sell-out Fringe show Michelle McManus @ The Musicals back to Edinburgh this year and then tour it around the country.
She is also working on Gaelic programmes with BBC Alba.
For the singer, she is hoping a highlight of 2014 will be getting involved in the opening ceremony of the Commonwealth Games.
"I'm so lucky, this is my 11th year since winning Pop Idol and I just can't believe I'm still working," she smiles, adding: "When I'm on the front page of Heat magazine at the end of the year when I've lost weight, I'll say it was all down to the Evening Times."