For society, there are also major implications in greater health service demand, lost industrial productivity and increased incapacity benefit payments.
The estimated cost to the national economy is £15 billion.
The publicity for my "timebomb" scenario was huge, and a 2004 evaluation of media coverage of my reports showed obesity became a bigger issue than either smoking or the MMR vaccine - both "hot topics".
Since then, obesity has hardly been out of the media whether in news stories, weight loss and exercise campaigns, feature articles, agony columns, surveys.
In any other field, this would be a publicist's dream, but traditionally health education programmes have tried to tightly control messages and information.
The obesity story has not stayed in its box. It has run and run, but it has also provoked soul-searching.
How much should we spend on school meals? Are parents of obese children bad parents? What are the limits and responsibilities of the state in taking action? What is the place for banning things? Should fat patients go to the back of the queue for NHS treatment?
I felt like the manager in the half-time dressing room at St James's Park on a bad day
Iconic stories and images have emerged: Jamie Oliver getting Rotherham cooking, mothers pushing meat pies through the school railings, people so desperate to lose weight that they opt for stomach stapling operations.
The electronic database of published medical journal articles (Pubmed) shows just over 114,000 on the subject of obesity over the last nearly 30 years.
Mum Amanda Broomhall believes we should use the word obese
This headline figure conceals an important trend. At the beginning of the 1980s, the figure was around 1,200, by the beginning of this decade it was over 4,000 and last year it had risen above 10,000 medical articles.
What does this mean? Medical research priorities often reflect public concern about the seriousness of a disease.
Obesity used to be the interest only of specialists. It has moved from the professional to the personal and the political.
Today, the word obesity arouses deep feelings and provokes strong opinions. It influences in ways that can't always be predicted.
A couple of years ago I was at a meeting to discuss action on obesity. The meeting was downbeat and people said very little.
I was annoyed: "where are the ideas?", "where is your enthusiasm?", "why can't we rise to the challenge" I asked them.
I felt like the manager in the half-time dressing room at St James's Park on a bad day.
The obesity epidemic is a national crisis - doing nothing is not an option
After the meeting broke up, one person crept back into the room and whispered to me: "We couldn't talk about it properly because someone obese was in the room."
Dividing someone's weight by the square of their height produces the Body Mass Index (BMI).
A BMI between 18.5 and 25 is a healthy weight, 25 to 30 is overweight, while anything over 30 is 'obese'.
'Labelled for life'
Recently, we were planning the results letter to parents following the National Child Measurement Programme.
The purpose of this initiative is to monitor children's health and well-being and aims to make parents aware of any potential problems with their child's weight so that they can seek professional help if needed.
Such data is also essential to track the problem at population level and target action appropriately.
The BBC News website is launching the "Scrubbing Up" weekly column, where leading clinicians and experts give their perspectives on issues in health
Each week, you will be able to have your say
The stumbling block became the wording of the feedback letter to individual parents.
At an earlier stage some child health professionals had argued against the idea of a school-based weighing and measuring scheme because it would stigmatise overweight or obese children and lead to them being bullied.
When the letter was field-tested with parents in focus group interviews there was a clear message that the term "obese" was unpopular.
They felt they were being personally blamed for their child's health, and that their child would be "labelled for life".
The majority of these parents felt that using the term "very overweight" in combination with the associated health risks was a better approach.
The 'O' word
Suddenly, having been walking on a firm path, we had stepped on to eggshells.
Some argued that the views of the focus-group parents should predominate: from now on it should always be "very overweight". Others felt that this was colluding with a form of denial and the real problem was that some parents were not facing up to or engaging with the need to act.
"Obesity" has become the new "cancer". A word that is taboo, that intimidates, that strikes fear, that promotes softer euphemisms.
In effect it has become an "O" word.
The gurus of change management often speak of the need for everyone to recognise a state of crisis in order to take action.
They use the metaphor of a burning platform.
Perhaps the word "obesity" is itself that burning platform.
Precisely because body size has become a personal, social and political issue, the use and meaning of words to describe it is important.
We cannot afford to alienate parents. They need to be engaged and active in helping to solve the problem.
On the other hand, the obesity epidemic is a national crisis. Doing nothing is not an option.
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