Obesity in infancy and childhood is a measure of adiposity that's a little more difficult to determine than the usual weight for height. In adults, the Body Mass Index or BMI is used to estimate the percent body fat. By most rigid definitions, in boys, a body fat mass of greater than 25% defines obesity, while in girls it moves up to greater than 32% body fat. It goes without saying that not all infants defined by the above criteria as obese will go on to become obese children. Likewise not all obese children will go on to become obese adolescents. And finally, not all obese adolescents will become obese adults . . . on the other hand many will.
The relationship between formula feeding and obesity implies breast fed infants have been given a step up in the fight to maintain fat mass within a non-obese range. The biologic plausibility relating the relationship between breast feeding and a protective effect from excessive body fat relies upon a few very nebulous factors. How might the intimate contact between mother and baby protect said child in later years from overeating? Is there some as yet undefined anti-obesity effect provided by the intimate contact of mother and baby? And what are the content factor or factors (often referred to) within breast milk that might modulate later eating practices? Infant formula might be deficient in some as yet not clearly defined hormone or protein factor which establishes weight control in the breast fed infant. Also, is there again some yet undiscovered factor that modulates adipose tissue proliferation and growth in infants and children while those bottle fed infants have no such modulation? And without those modulating factors, fat storage becomes uncontrolled in later life. Finally, might taste function become changed by the suckling of infant to breast such that breast fed infants spend a lifetime eating less due to the chemical environment of the breast milk on the developing taste organ? So many theories, so little evidence.
In all, the epidemiology of obesity as it relates to breast versus bottle feeding has numerous seemingly plausible biologic explanations for the observation that more obese children and adolescents were bottle fed, but offers nothing concrete. The ultimate answer to this question would involve a study taking all newborns, randomize them to either a breast feeding or bottle feeding regimen and measure their change in fat mass over the next thirty years. Short of that, observational studies with all the confounders and interfering factors will cloud the relationship between formula feeding and obesity.
Without citing studies, the hypothesis that formula feeding determines or sets the stage for later obesity presents a dilemma for treating the problem. Are the issues related to obesity not related to environmental factors, such as the number of hours watching television, and the family focus on good nutrition and physical activity? If the deterministic model of obesity is adopted, then treatment with lifestyle changes would be assumed to have no impact as the determining factor (breast versus formula feeding) has already occurred and damaged the system. The cornerstone of treating childhood and adolescent obesity are modifications in physical activity, diet and lifestyle such that more calories are burned and less time is spent in sedentary activities such as television watching and video games or computer games.
Finally, a study was published in the American Journal of Clinical Nutrition (2007;85:1578-1585) titled:
Infant Feeding Method and Obesity: Body Mass Index and Dual–energy X-ray Absorptiometry Measurments at 9-10 y of Age From the Avon Longitudinal Study of Parents and Children.
The long-winded title of the study addressed one of the critical factors in determining obesity, the measurement of fat mass. Since BMI only estimates percent body fat, a more accurate measure using Dual-energy X-ray Absorptiometry (DEXA) was used in children age 9 to 10 years from a large birth cohort. The goal of this study was to determine the relationship between percent total body and trunk adiposity and prior breast versus formula feeding. Of interest was the association between breast feeding and a number of factors. Included in that list and associated with breast feeding was less television watching, higher education, higher socioeconomic class, lower % who smoked and lower maternal BMI. Using multivariate linear regression the association between breast feeding and total body and trunk fat persisted (but was attenuated) after adjustment for all the above factors. Which points to the possibility that factors characteristic of those inclined to breast feed their children are determining fat mass and not the breast milk per se.
In conclusion there isn’t a definitive answer to this question and probably never will be. Wild speculation has led breast feeding advocates to run amok with notions of near perfect populations of babies if exclusively breast fed. Those same advocates recite lower rates of nearly every disease known to man including obesity, again, if all babies were breast fed. There is no doubt in my mind that breast feeding benefits the baby (and mother) in many subtle ways, but preventing obesity? I’m as always . . . a skeptic.
The relationship between formula feeding and obesity implies breast fed infants have been given a step up in the fight to maintain fat mass within a non-obese range. The biologic plausibility relating the relationship between breast feeding and a protective effect from excessive body fat relies upon a few very nebulous factors. How might the intimate contact between mother and baby protect said child in later years from overeating? Is there some as yet undefined anti-obesity effect provided by the intimate contact of mother and baby? And what are the content factor or factors (often referred to) within breast milk that might modulate later eating practices? Infant formula might be deficient in some as yet not clearly defined hormone or protein factor which establishes weight control in the breast fed infant. Also, is there again some yet undiscovered factor that modulates adipose tissue proliferation and growth in infants and children while those bottle fed infants have no such modulation? And without those modulating factors, fat storage becomes uncontrolled in later life. Finally, might taste function become changed by the suckling of infant to breast such that breast fed infants spend a lifetime eating less due to the chemical environment of the breast milk on the developing taste organ? So many theories, so little evidence.
In all, the epidemiology of obesity as it relates to breast versus bottle feeding has numerous seemingly plausible biologic explanations for the observation that more obese children and adolescents were bottle fed, but offers nothing concrete. The ultimate answer to this question would involve a study taking all newborns, randomize them to either a breast feeding or bottle feeding regimen and measure their change in fat mass over the next thirty years. Short of that, observational studies with all the confounders and interfering factors will cloud the relationship between formula feeding and obesity.
Without citing studies, the hypothesis that formula feeding determines or sets the stage for later obesity presents a dilemma for treating the problem. Are the issues related to obesity not related to environmental factors, such as the number of hours watching television, and the family focus on good nutrition and physical activity? If the deterministic model of obesity is adopted, then treatment with lifestyle changes would be assumed to have no impact as the determining factor (breast versus formula feeding) has already occurred and damaged the system. The cornerstone of treating childhood and adolescent obesity are modifications in physical activity, diet and lifestyle such that more calories are burned and less time is spent in sedentary activities such as television watching and video games or computer games.
Finally, a study was published in the American Journal of Clinical Nutrition (2007;85:1578-1585) titled:
Infant Feeding Method and Obesity: Body Mass Index and Dual–energy X-ray Absorptiometry Measurments at 9-10 y of Age From the Avon Longitudinal Study of Parents and Children.
The long-winded title of the study addressed one of the critical factors in determining obesity, the measurement of fat mass. Since BMI only estimates percent body fat, a more accurate measure using Dual-energy X-ray Absorptiometry (DEXA) was used in children age 9 to 10 years from a large birth cohort. The goal of this study was to determine the relationship between percent total body and trunk adiposity and prior breast versus formula feeding. Of interest was the association between breast feeding and a number of factors. Included in that list and associated with breast feeding was less television watching, higher education, higher socioeconomic class, lower % who smoked and lower maternal BMI. Using multivariate linear regression the association between breast feeding and total body and trunk fat persisted (but was attenuated) after adjustment for all the above factors. Which points to the possibility that factors characteristic of those inclined to breast feed their children are determining fat mass and not the breast milk per se.
In conclusion there isn’t a definitive answer to this question and probably never will be. Wild speculation has led breast feeding advocates to run amok with notions of near perfect populations of babies if exclusively breast fed. Those same advocates recite lower rates of nearly every disease known to man including obesity, again, if all babies were breast fed. There is no doubt in my mind that breast feeding benefits the baby (and mother) in many subtle ways, but preventing obesity? I’m as always . . . a skeptic.
