British researchers say children from wealthy middle class homes are more likely to be overweight or obese than those from poorer backgrounds.
The findings by researchers from the Institute of Child Health at University College London and Great Ormond Street Hospital to some extent dispel the myth that the poorest families have the worst diets as they suggest that the risk of obesity is greatly increased in line with family income.
The researchers put this down to the rise in the numbers of highly-paid working mothers - who are often forced to leave a child in the care of a nanny or a nursery who take over control of the child's diet and physical exercise.
Other suspected factors include a high consumption of snack foods and sweetened drinks, long hours spent watching television and low rates of breastfeeding which has been found to prevent obesity.
The researchers examined a total of 13,113 children aged 3 years who born between 2000 and 2002 in the United Kingdom, who had complete height/weight data and parental employment histories.
The parents were interviewed when the child was aged 9 months and 3 years, and the child's height and weight were measured at 3 years.
Being overweight, including obesity, was defined by the International Obesity Task Force cut-offs.
The study found that children from families with an income between £22,000 and £33,000 were 10 per cent more likely to be overweight or obese than those from families with an income of less than £11,000.
When the family income was £33,000 or more, children were 15 per cent more likely to be overweight than the poorest children.
Health experts say the results are a wake-up call to middle class families who very often assume their children are living healthy lives and shows that obesity is an issue that affects middle class families as well as low income groups.
The study showed that by the age of three, 23 per cent of children were overweight and this was were more likely to be the case if their mother had taken up any work since their birth.
The researchers found that long hours of work by the mother, rather than lack of money, may have an impact on young children's access to healthy foods and physical activity.
The researchers say having a working parent with less time could increase a child's consumption of snack foods and/or increase television use and children were more likely to be overweight if the mother reported that she 'did not spend enough time with her child because of work'.