I read somewhere that a baby's weight at birth may predict if that baby will be at risk for obesity later in life. Is that true? Is it realistic to think that one can prevent obesity, even starting as young as infancy?
The whole issue of early prevention of obesity still remains complicated. However, there is a steady flow of new scientific studies, each assembling one more piece of a puzzle. Given the increased prevalence of this critically important public health issue - it is anticipated that obesity-induced diseases will cost the healthcare system plenty of money in future - most experts feel that obesity prevention measures must start in infancy.
The big picture is that rapid weight gain during the first weeks or months of infancy predicts obesity later in life. In a recent paper from Harvard School of Public Health - spearheaded by one of the world's most respected experts in the field of early predictors of obesity - Dr Matthew Gillman and his research team concluded that the weight status in the first 6 months of life was associated with a sharp increased risk of obesity at the age of three years.
Dr Gillman's group in Boston did something that was unique in three ways, thus making their findings extra impressive:
- Firstly, they gathered data of babies' length both at birth and at 6 months in addition to weight alone (Other previous studies only looked at weights).
- Secondly, they were able to adjust their data for the gestational age of the babies (that is, how long the babies were in the mothers' wombs).
- Lastly, they considered factors which were never previously considered such as the dad’s weight and body mass index (BMI) in addition to the mothers' values. (BMI is calculated by dividing the weight twice by the height - a standard value to define the degree of obesity).
Their conclusion, that rapid weight gain in the first 6 months of life predicted a 40% higher probability of obesity at 3 years of age, was independent of other causes such as socioeconomic status, maternal smoking, weigh gain during pregnancy and the mom’s pre-pregnancy BMI.
There are two other important factors to consider in the early prevention of obesity. One is the use of essential omega three fatty acids (DHA) while pregnant, and the other is the duration of breastfeeding.
The jury on DHA is still out. Previous studies suggested that an increased intake of DHA by pregnant moms might be associated with a reduced risk of obesity in children.
Dr Gillman's group at Harvard did not find that to be true in their study. However, there are numerous other reasons for a pregnant patient to take 200mg of DHA daily. The two main convincing reasons are better brain development and improved visual outcomes. A third, perhaps less convincing reason, is better immunity in babies exposed to DHA while in the womb (For more information on the benefits of DHA during pregnancy see www.DHAomega3.org).
In the Gillman data, breastfeeding was independently associated with a lower prevalence of obesity at age three, thus confirming other previous studies which showed the same results. However, when the authors speculated why breastfeeding played such a key role, they were less certain of the exact mechanism.
It is speculated that when a baby is weaned early, the risk of subsequent overfeeding may explain why those babies are at a higher risk of being obese at age three. The authors were not able to examine low caregiver responsiveness to child feeding cues in their research, but admit that it may be important in predicting the risks for later obesity.
In terms of preventing obesity by focusing on factors during pregnancy and infancy, here are some measures to consider:
- Ideally, ensure that both parents have a BMI under 25.
- Breastfeed for as long as possible. When weaning babies early, be careful to not overfeed them by giving excessive amounts of formula (Optimally, no more than 150 ml per kg per day for full term babies).
- Even though data may not yet be fully conclusive, consider early exposure of DHA beneficial. The majority of current formulas have DHA added, but not all formulas contain the minimum amounts as suggested by the WHO.
- Avoid rapid weight gain in the first 6 months of life since it increases the risk of obesity by age three by 40% (Rapid weight gain refers to a pattern of gain where a baby's weight accelerates faster than the length, and where the numbers cross a few percentiles faster than expected).
Ultimately, the reasons why babies become obese later in life remains very complicated. Although genes play a major role, there are some things parents can attempt. For more information online, see the electronic pages of Pediatrics, April 2009 (www.pediatrics.org).
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