In the Americas, 31 percent of children are overweight or obese.

London - Once upon a time, it was politely termed puppy fat — dismissed as something or nothing that children would naturally grow out of.

However, increasingly scientists believe being an overweight child is far more dangerous for future health than we previously thought.

It doesn’t seem surprising to learn that obese children are more likely to have high blood pressure, high cholesterol and even signs of the early stages of type 2 diabetes — a disease traditionally associated with overweight adults — as an authoritative review published in the British Medical Journal confirmed.

But, alarmingly, the review also found that children who are simply overweight, rather than obese, are similarly affected, although to a lesser extent. ‘Obese’ is defined as having a body mass index (BMI) of 30 or more, and ‘overweight’ as 25 to 30. This is far from the first time the dangers of being overweight as a child have been highlighted.

Back in 1999, for example, a paper in the International Journal of Obesity and Related Metabolic Disorder warned that the risk of cardiovascular disease and dying from any cause in adulthood was raised ‘among those who were overweight during childhood’.

‘What we don’t yet know is if being overweight as a child naturally leads to an increased risk of these things like cardiovascular disease,’ says Professor Russell Viner, from University College Hospital, London. ‘My view is it probably does, but this leads to other questions we don’t yet know the answer to, such as: does losing the weight as a child reduce your risk and is there a particular age that is key?’

Around 13 per cent of four-year-olds are overweight (9 per cent are obese). The problem gets worse with age — by the time they leave primary school at 11, 14 per cent are overweight (19 per cent are obese).

Many parents may not realise their children are too heavy — various studies have found as many as 75 per cent of parents of overweight children underestimate their child’s weight.

‘There was a study two years ago that found 50 per cent of parents of obese children think their kids are “just right”,’ says Paul Gately, a professor of exercise and obesity at Leeds Metropolitan University. ‘We also did a study among healthcare professionals and found that 75 per cent underestimated the weight of an overweight child and 50 per cent underestimated the weight of an obese child.There has been a normalisation of obesity.’

Professor Viner agrees: ‘Almost a third of adults are now obese and so our understanding of what is a normal body shape has shifted. It is perfectly healthy for a child aged four to eight to have the top and bottom of their ribs visible, but this is often perceived as underweight.’

Our cultural messages are all about building children up. As Professor Gately says: ‘It starts early — people ask about babies: “Is he a good feeder?” We are developing an over-active appetite from a young age — we bottle-feed babies so they finish a bottle rather than take as much as they need from the breast.

‘We tell them to eat up or they won’t get a pudding and we allow them to snack, which is not going to do anything to help them develop healthy eating habits. I am a father of four and my children as babies fell below the expected growth patterns and we got referred to specialists.’ He says this would not have happened had it been the other way around. ‘Yet it is possible for babies to be obese and it is becoming increasingly common to be born obese. Big babies tend not to lose their weight and are more likely to become overweight adults, as are underweight babies who suddenly put on weight in the first six months.’

The situation isn’t helped by the fact the ways to measure children’s weight aren’t straightforward. For instance, you can’t just stick your child’s details into one of those online tools that calculates BMI, because age also needs to be taken into consideration. There are other systems that involve measuring a waist-to-hip ratio. ‘None of them is simple for parents to perform,’ says Professor Gately.

Furthermore, while it may be obvious when a child is very obese, it’s hard to define the borderline cases. ‘Some kids do have some puppy fat — and there was probably some evolutionary protective reason for it,’ he says. ‘The puppy fat stage tends to be just before a major growth stage, so in early childhood and then again around the ages of six or seven. As they grow, they lose it.’

It’s important to understand that while some obese children may suffer from obvious signs of unhealthiness, such as breathlessness or tiredness, many others don’t have other symptoms, yet are laying down problems for the future, says Dr Ahmed Massoud, a consultant paediatrician at The Portland Hospital in London and Northwick Park NHS Hospital in Harrow.

He says: ‘We don’t yet know if an obese child losing the weight when they get older means they remove the risk to their health. The key is to stop the problem before it begins.’ - Daily Mail