The developed world loves to put on food drives, places to donate canned goods to the needy. It is an easy feel-good thing to do. But it may be unnecessary, according to findings in The European Journal of Public Health.

Instead of going hungry, the Millennium Cohort Study (MCS), which tracks nearly 20,000 families from across the UK and made measurements when the children were aged 5 and again at age 11, finds that obesity is rampant in poor kids. At age 5, poor children were almost twice as likely to be obese compared with their better off peers. 6.6% of children from families in the poorest fifth of the sample were obese while the figure for the richest fifth is just 3.5%. By the age of 11 the gap has widened, nearly tripling to 7.9% of the poorest fifth are obese.

The researchers looked for any explanation except eating too much; smoking during pregnancy, which is obviously far less than 50 years ago when obesity was not a problem; breastfeeding, a good way to penalize poor mothers, since they are probably in dual-income families, and more. Obviously the most likely factor is that the mother is obese.

They also compared the frequency of sport or exercise, active play with a parent, hours spent watching TV or playing on a computer, journeys by bike and the time that children went to bed. It also compared dietary habits such as whether the child skipped breakfast as well as fruit and sweet drink consumption. The study found that doing sport more than three times a week played an important role, as did an earlier bedtime and regular fruit consumption which were both positively associated with downward movement in weight categories. However, maternal smoking during pregnancy and a mother's BMI were negatively associated with downward movement across weight categories. Overall, the study found that markers of 'unhealthy' lifestyle here could mean as much as a 20% additional risk of obesity for a child.

The analysis in this study suggests better targeting. The authors say that more research should be undertaken to increase effectiveness, given that the processes involved in the development of fat gain in children involve social, environmental, and biological factors.