Louise Redknapp discovers first hand the dangers of the current obsession with being stick thin when she undertakes an extreme crash diet and exercise regime in an attempt to drop to a US dress size zero in just 30 days.

In The Truth about Size Zero Louise undergoes a punishing plan to dramatically lose her trademark curves and attempt to drop two dress sizes, this is a TV show that will get engaage all who watch it.

The TV presenter, who was voted FHM’s Sexiest Woman of the Decade, is usually a size eight, but in The Truth About Size Zero she attempts to get down to a UK size four.

After 17 years in the spotlight Louise is all too aware of the pressure to be thin and she agrees to put normal life on hold to find out more about the size zero trend and expose it for what it really is.

“I grew up in the entertainment and music industry,” she says, “I went to stage school and I always wanted to be in entertainment and I have always felt even at a size eight that I have never quite been skinny enough….there was always (the pressure) that if I could have lost half a stone it would have been better.

“It is such a lot of pressure on a young woman and if I was feeling that, I know a lot of other young women were also feeling that.”

In The Truth About Size Zero she finds out what ‘lollypop ladies’ really do to gain their size zero status and at what cost. She undertakes a punishing diet and exercise regime for the month long experiment.

Throughout this process Louise is closely monitored by celebrity nutritionist Dr Adam Carey who warns her of the dangers of crash dieting.

Dr Carey says: “I think the current vogue is macabre. I think it is obscene and it is very unhealthy.”

After her first consultation with Dr Carey, Louise says: “Everything he said shocked me. It’s a shame. If every woman in the country, or every woman in the world, that wants to lose weight and become really skinny, if they could all just have half an hour sat down with a doctor telling them exactly what’s going to happen to them, I think you’d get very few of them that would carry on with it.”

But Louise is convinced that she can only be really qualified to speak out about the tyranny of thin by going through the experience first hand.

To kickstart the regime Louise travels to LA where she enrols with Bootcamp Barry, a military-style fitness and diet guru to stars such as Teri Hatcher, Katie Holmes and Jenny McCarthy.

She takes part in his fitness boot camp and also trawls the boutiques to shop for a size zero dress as her ‘thinspiration’.

She also meets up with old friend Denise Van Outen who tells her about how she was told to lose weight when she first moved to LA.

Bootcamp Barry sets out Louise’s diet and exercise plan for the next 30 days. She has to run three miles a day before completing a further punishing hour of cardio and weights in her home basement gym.

Back in the UK she also talks to Mel C who suffered from anorexia throughout her time as a Spice Girl and was cruelly labelled Sumo Spice when she subsequently resorted to binge eating.

Louise also visits patients at the Rhodes Farm Clinic for eating disorders in North London and is moved to tears when she sees just where the size zero trend hits the hardest.

Just a few days into the plan, Louise begins to struggle with her busy life as a working mother on only 800 calories a day. And the time consuming exercise regime also impacts on family life.

“I completely underestimated how hard this would be,” she says.

Two weeks into the diet, Louise goes for her mid-way appointment with Dr Carey. The diet is taking its toll. She has a cold, can’t sleep, is tired, bored, irritable and hungry. Dr Carey urges her to quit.

Louise also visits her old stage school, the Italia Conti Academy of Theatre Arts, to warn the pupils about the true horrors of crash dieting.

The final strait sees Louise returning to LA where she goes on a mad dash tour of weird and wonderful alternative routes to size zero. And it’s back to Barry’s Bootcamp for one last time.

On the last day of the diet, Louise returns to Dr Adam for her final check up. The regime has impacted on her health.

Her 30 day fast is now over and she can fit into the size zero dress.

Two months on, Louise has made a full recovery. She is once again enjoying her food and loving her curves.

ITV1 Network Wednesday 7 March 9:00 PM to 10:30 PM