Babies are all born with an in-built, near-perfect, appetite control mechanism, so why are there so many obese children in our schools? by Jo Carlowe
Data from the Health Survey of England reveals that 31% of boys and 29% of girls aged between 2-15 years old are currently overweight or obese.[i] According to The Early Bird Study in the Journal Pediatrics, [ii] most of this excess weight is gained before the age of five.
In establishing the causes of childhood obesity, experts cite factors ranging from sedentary lifestyles through to the mother’s diet during pregnancy. But most recently, the spotlight has shone on the months immediately after birth when the baby is drinking an exclusive diet of either breast or formula milk. The thinking now is that this time is crucial in determining future eating habits and body weight.
Just as there are critical periods in brain development that allow babies to reach milestones such as the ability to track movement with their eyes or acquire language, so there is now mounting evidence that babies also have a ‘developmental window’ in which to set their appetite. If during this period the baby’s natural ability to self-regulate food intake is overridden, the infant will likely put on weight rapidly, setting into motion biological and behavioural changes that will predispose him to a lifelong fight against flab.
Many studies support the theory that faster growth in infancy (measured by upward percentile crossing for weight or length on baby charts) increases the risk of obesity, cardiovascular disease, raised blood pressure, stroke and type 2 diabetes later in life.
In a British Medical Journal paper, the researchers note that obese babies have ten times the risk of being obese later in life. More tellingly, it’s not just obese babies that risk future weight gain, but rather infants who grow rapidly during their first few months of life (even if not obese). The findings reveal that such babies have six times the risk of future obesity.[i]
Scientists across the world are starting to back-up these findings. Dr Nicholas Stettler, Nutrition Fellow at The Children’s Hospital of Philadelphia, USA, estimates that 20% of the risk of obesity at the age of 7 years can be attributed to having a rate of weight gain in the highest quintile in the first 4 months of life.[ii] While a similar study from Holland shows that babies who gain weight rapidly in the first three months or life are significantly more likely to be obese by the age of 19.[iii]
These papers on human infants lend weight to animal research dating back to the 1960s. In one study, rats raised in small litters, that fed more in the suckling period than those in bigger litters, were larger as adults.[iv] Likewise, baboons that were overfed in infancy had greater fat mass in adulthood.
Yet when in 2004 Professor Atul Singhal, of the Childhood Nutrition Research Centre at the Institute of Child Health, University College London, published a paper in the Lancet to suggest the same held true of humans, it was met with criticism.[v]
“There was this idea that there is no such thing as too much growth in babies,” says Professor Singhal.
Yet the impact of this overfeeding is substantial. Professor Singhal and colleagues had assigned babies to a regime in which half received a standard formula and half a growth-promoting formula. In a second study, he compared formula fed babies to breast-fed ones. The results were stark – 6-8 years later the breast fed babies had healthier levels of fat in their bodies and better blood-pressure readings than the formula-fed one. Similarly, the fat mass in the children randomly assigned the nutrient-enriched formula was 22-38% greater than in those who received the standard formula. [i]
Singhal’s findings support the idea that if babies grow at a steady, rather than accelerated, pace during their first months of life are at less risk of obesity and associated health problems than those who grow rapidly.
So why do these large, some might say ‘bouncing’ or ‘bonny’ babies face a greater risk of obesity later in life simply by growing so well early on?
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Jo Carlowe is an experienced freelance journalist and editor.
She writes features and news for national newspapers, consumer magazines, medical and professional journals.