Obesity among Scotland's children is at alarming levels (some one in six boys between two and four-years-old is classed as obese for example) but today there is even more bad news.

According to new research, children in Scotland are among the least active in the world. Indeed, in the survey of 15 countries, Scotland came right at the bottom in two categories, scoring an F for overall physical activity and the same score in the category judging how much time children spend in front of television and their computers. The answer is too much.

Although the poor rating for Scotland should probably come as no surprise - experts have been warning of the problem for many years - the research must act as a catalyst for reform. Scotland is facing the potential of an obesity epidemic and is still not doing enough to tackle it.

John Reilly, professor of physical activity and public health science at Strathclyde University who was involved in the research, points out that there is no magic solution.

But, to its credit, the Scottish Government does have an action plan on the subject that focuses, among other areas, on encouraging parents to help their children eat well and exercise more; there are a number of educational initiatives targeting these areas.

There is also an emerging consensus on the problem, which is that the central focus of a solution should be physical activity rather than diet. Sir Harry Burns, the former Chief Medical Officer for Scotland, among others, has put great emphasis on lack of activity as the key issue. Lack of exercise, he says, is as damaging to our health as smoking, alcohol abuse and diabetes combined.

The research has also demonstrated that bad habits start young, which means the solutions need to start in the early years too. Steven Blair, an American professor of public health, pointed out recently that Scotland is not far behind the US on the issue and, like Sir Harry, he says the greatest emphasis should be on physical activity rather than eating less. "In simple terms," he says, "we are talking about changing the mindset from thinking 'I must go on a diet' to 'I must become more active'."

It will not be easy and will involve changing cultural norms which have crept up on Scots in recent years; norms that suggest it is OK for children to spend many hours in front of screens.

If there is to be a change for the better, it will have to be change on many fronts involving health visitors in the very early years of a child's life through doctors and teachers as they grow up, as well as parents. It is parents who can encourage their children to walk to school, for instance, spend less time on their computers and get out to Scotland's great green spaces.

It is this preventative approach in the early years of childhood, supported by government education and campaigns, that has the potential to tackle the crisis. The NHS is already creaking under the strain of treating obese Scots. The mission now must be to help the next generation become healthier and fitter.