Casey Donovan was dangerously overweight, but with ironman legend Guy Leech's help she's already on the right track.

Training former Australian Idol winner Casey Donovan is one of the most ambitious fitness projects I've ever tackled. Not because she's overweight, it's more because she's only 18 years old.

It's an age where you feel bulletproof. You can hide a lot of bad habits in a teenage body and get away with it. So trying to convince Casey that it's time to stop eating junk food while her friends drink and party every night is a challenge.

An adolescent is also a lot more susceptible to what people think. Casey is a kid who was thrust into every lounge room in the country when she won Australian Idol at the age of 16, and that brings a whole new set of challenges to my team.
In every session she's done with us so far we've concentrated on convincing Casey to believe us.

Unfortunately, she's felt let down by experts - including doctors - who she thought would support her, but instead told Casey she was 'born to be fat' and that there was no chance she'd ever lose the weight. Consequently, she gave up on herself.
The first thing we tackled with Casey was her diet. Adopting better eating habits is an important way to lose weight, because at Casey's size you're too large to start exercising intensely straight away.

Soft drink and fast food were her demons. She never drank water and ate takeaway food daily.

Within a week of daily walking and cutting back on bad food, Casey started sleeping through the night and that has changed her whole outlook.

She now falls asleep at 10pm and sleeps solidly for 10 hours. She's back in the real world, instead of living like Dracula and falling asleep at 4am, like she used to in the past.
Casey's also better able to concentrate and write songs because she has more energy.

I see Casey as the poster girl for childhood obesity. I'm confident that over the next six months we'll be looking at a new person. She's going to be quite athletic as the weight drops off.

In this first month alone, Casey has shed an amazing 13cm off her waist. I've told her to throw away the scales, because she's losing fat but replacing it with muscle, which is denser.

Last year she gave up smoking, so I know she's got determination. Casey's family is also supporting her all the way. They've even changed the food they put in the pantry, just to help the cause.

She's really giving this her best shot because she wants to feel better and help herself. A brilliant career beckons and I'm very happy to help her make it happen.

Casey's immediate rescue plan

• Walk six days a week for between 40 to 60 minutes each walking session.
• Replace soft drink with water and no late-night snacking.
• Cut down on takeaway food. Definitely don't have it every day!
  

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