Skipping breakfast and irregular sleep patterns have been identified as key reasons why children may become dangerously overweight in research that sheds new light on the obesity epidemic.
The study, led by academics from University College London, challenges the widely-held view that soaring childhood obesity rates are caused solely by overeating.
Lifestyle factors and the environment a child is brought up in play a significant role in their chances of becoming obese, the researchers found from examining records of the health and circumstances of children born into 19,244 families across the UK between September 2000 and January 2002.
"This study shows that disrupted routines, exemplified by irregular sleeping patterns and skipping breakfast, could influence weight gain through increased appetite and the consumption of energy-dense foods," said Prof Yvonne Kelly, from UCL's department of epidemiology and public health, who led the research.
Her team’s analysis of data collected by the Millennium Cohort Study showed that children who do not have a regular bedtime or who get too little sleep are at risk of gaining excess weight. Being born to a mother who smokes is another important factor in predicting whether a child will become overweight or obese, they found.
The researchers also concluded that a child's consumption of sugary drinks or the amount of television they watch are not strong predictors of who will gain an unhealthy amount of weight. The findings are published on Friday in the American medical journal Paediatrics.
Prof Neena Modi, the president of the Royal College of Paediatrics and Child Health, said: "This paper not only highlights this point but also emphasises the multifactorial nature of obesity; put simply, it isn't just caused by eating too much. This research points to the role of environmental pressures on children's weight such as having an irregular bedtime or insufficient sleep; in other words children are very vulnerable to multiple influences."
The study also confirms the already well-established increased risk of a child born to an overweight or obese mother ending up with excess weight themselves. But breastfeeding and the early introduction of solid food make no difference to their risk, the researchers found.
It found that 83.3 per cent of children in the UK had a stable, non-overweight body mass index. Almost one in seven, or 13.1 per cent and who are more likely to be girls than boys, have a moderately increasing BMI. Another 2.5 per cent have a steeply increasing BMI. Pakistani, Black Caribbean and Black African children were more likely to belong to that group. A tiny number, 0.6 per cent, were already obese by the age of three.
Prof Modi backed the authors' conclusion that greater intervention in a child's early life is needed to try to alter their environment and reduce the chances of them becoming overweight.
“We have long drawn attention to the importance of early intervention in tackling childhood, and indeed adult, obesity. The earlier the action, the higher the chance of preventing obesity taking a hold and adversely affecting lifelong health,” she said.
“To reduce the extremely worrying prevalence of child obesity and overweight, a combination of measures is required. These include support for parents before, during and after pregnancy, and education of families about the importance of leading healthy lives.
“As this paper shows, if children are set on the right trajectory early in life, they are much more likely to remain healthy as they move into adulthood. Focusing on getting it right for children will mean getting it right for adults too.”
Alison Tedstone, the chief nutritionist at Public Health England, said: "Skipping breakfast can be an indicator of a poor diet, which can predispose to weight gain. It's important that families make health choices, including for breakfast. This is why we're working with the food and drink industry to make the food children eat healthier, starting off with reducing some of the sugar content."