THE Countdown theme tune is playing on a loop in my head. There is a lot to talk about and Dr Catherine Calderwood is a woman much in demand.

Meeting at her office among the maze of corridors at St Andrew's House in Edinburgh, the Chief Medical Officer for Scotland apologises for having to squeeze me in between her last meeting and hotfooting it to catch a flight to London. "It is busy all the time," she smiles. "There is no easy day."

Calderwood's remit involves advising government ministers on health policy alongside overseeing the clinical effectiveness of healthcare services. She was appointed in 2015, replacing Sir Harry Burns who had stepped down the previous year.

Before wading into the quagmire of the nation's health, let's first rewind a bit. The eldest of two daughters, Calderwood grew up in Belfast. She was born in 1968, the year the Troubles in Northern Ireland began.

Calderwood, 48, speaks with candour about her childhood. "That was life and what you got on with," she says. "You had soldiers in the streets with guns, armed police and bomb scares but I suppose as a child that was what I knew."

Did she know people who were affected? "Two neighbours of mine were shot." There is a set to her jaw that indicates even after all these years, the memory remains crystal clear.

Calderwood's father Jimmy is an orthopaedic surgeon and her mother Lesley a psychiatrist. "My dad as an orthopaedic surgeon had a lot of bad injuries to deal with," she says. "The IRA used to do the punishment shootings with kneecappings. The idea was that people would never walk again.

"The orthopaedic surgeons in Belfast got them walking again, so the IRA started to shoot people in the ankles instead. My childhood is stories like that and my dad operating with bullets ricocheting off the operating theatre on the Falls Road."

Calderwood knew from an early age that she would become a doctor. When her parents recently moved house, she found some teenage diaries where, among the scribblings on future dreams, was the bold goal to "find a cure" for something.

She studied medicine at both Cambridge University and Glasgow University, doing her clinical training in the latter city. Alongside her role as CMO, the consultant obstetrician and gynaecologist still runs an antenatal clinic at Edinburgh's Royal Infirmary.

Calderwood chose to specialise in that field after doing a medical elective at a Uganda hospital in 1990. She recalls crude facilities with no running water and a curtain-free row of beds in the labour ward.

"After giving birth, the women rinsed out their big wrap dresses and wiped the bed clean themselves. They then wrapped the dress back on with the baby inside and off they walked."

Her experiences in Uganda left an indelible mark. "One night there was two women who needed a caesarean section, but only one set of instruments, one set of greens, one theatre and one doctor to do it.

"He had to choose who was going to have a caesarean section and whose baby we were going to leave to die.

"I was in my twenties and couldn't get my head around how you decide."

The words of the doctor have always stayed with her. "He chose the wealthier woman and explained it was because her baby was more likely to survive into childhood. But also, if she had a caesarean section, she would come back and pay for care in her next pregnancy.

"The poorer woman wouldn't have had money to pay and when the next pregnancy came around she would potentially labour away from hospital when having a scar is then a risk to her life."

It was a stark lesson on the realities of social inequality that Calderwood didn't take lightly. From the outset of our conversation she is at pains to stress her job "is one of the few senior civil service roles" that is independent of government.

"If there was something I didn't agree with in government policy I can [question that]," she says. "I feel it is very important because from my point of view it is the Scottish people I'm representing."

Calderwood views an ageing population and ever greater pressures on the NHS as among the biggest health challenges facing Scotland.

"People are living longer, but that is a good thing," she says. "We sometimes see that as a negative and talk about older people living longer as if it is a burden. I don't like that. We have to be very clear that actually people living longer is a success for the health service."

Current projections suggest that the population of Scotland will age significantly, with the number of people aged 65 and over increasing by 53 per cent between 2014 and 2039.

"We know that people will then have more diseases," she says. "They will live longer with those illnesses and need more care both in the health service and in social care. At a time of financial constraint that is very difficult."

Changing the mindset on how we value and prioritise our health is crucial, she says. "The prevention side and keeping people healthy is really important. Our job is as much to keep people out of the NHS as it is to treat them when they are in the NHS."

At its heart is what she has dubbed "realistic medicine", a model which places the person receiving health care at the centre of the decision-making process. In short, doctors should spend more time listening to their patients in order to avoid unnecessary treatments.

As Calderwood puts it: "Trying to make health policy very real so that it is not just St Andrew's House churning out 'you will do this' but actually finding out what the pressures are and how we can help."

Tackling the health issues related to smoking, she believes, is set to become one of the success stories based on the Scottish Government target of a tobacco-free nation by 2034.

"Tobacco-free means less than five per cent smoking and I think we will reach that. They have in New Zealand with the same sort of ideas; some carrot, some stick. Banning smoking in public places was the first big success and the figures are that smoking is coming down."

Figures from 2004 show that among 15-year-olds in Scotland, 24 per cent of girls and 15 per cent of boys smoked regularly. It is now seven per cent. "Teenage smoking tends to be a mirror for the future and our teenagers seem to be more sensible than the adults before them," she says.

Many of the successful strategies used for tobacco, she says, could be applied to another issue that ranks high on her agenda: obesity. "There are now more people in Scotland who are obese than not obese," she says. "Two-thirds of our population are obese."

Is obesity the new smoking? "I have been quoted as saying sugar is the new tobacco," she says. Calderwood wants to address what she describes as an "obesogenic environment" where everything around us – from advertising to food labelling – actively encourages us to eat.

"It is wrong to say: 'Why don't people just lose weight? Why don't they eat less? Why don't they exercise more?' Because that is putting it on the individual and it is much more complex than that."

Calderwood is leading the Taskforce for the Improvement of Services for Victims of Rape and Sexual Assault, while under the "realistic medicine" umbrella her next project is finding ways to have more joined-up thinking between education and health literacy.

When her brain isn't whirling with statistics and strategies, any spare time is spent at home in Edinburgh with her children Lily, 15, Anna, 14 and George, 11. "I think they are a bit bewildered by my job," she admits. "They understand the doctor part, but this is very different.

"As teenagers they don't like the fact that I'm on TV. Their teachers are always saying: 'I saw your mum on TV.'

"But they just roll their eyes and say: 'Oh mum, you are so embarrassing …'"