Last Reviewed: September 2011
Make An Informed Decision
About obesity
Formula? No Thanks. I'm watching my waistline.
Babies don’t get to choose whether they are fed breast milk or formula, but you do. And since your choice can affect your child’s healthy development you need to get all the facts.
We don’t usually associate obesity with babies. However, recent studies show what babies eat and how they are fed can affect their risk of obesity later in life.
Research shows breastfed babies are at reduced risk for obesity later in life, compared to formula-fed babies. In fact, the evidence suggests breastfed babies have 14 – 33% less risk of becoming obese later in life, compared to formula-fed babies. The longer babies are breastfed (up to 9 months), the lower their risk for obesity.
Why talk about waistline?
We don't measure babies' waistlines. However, we do measure adult waistlines because waistline measurement is an indicator of obesity-related health risks. Adults with waistlines above certain levels have been shown to have greater risks for type 2 diabetes, hypertension and heart disease. Obesity is a growing health concern - preventing it is important.
How does breastfeeding protect children from obesity?
While researchers are still investigating exactly how breastfeeding protects against obesity, they have identified at least two factors that may play a role:
- The act of breastfeeding
When you breastfeed, your baby is an active participant in feeding. Research shows breastfed babies suckle differently and are more able to control how much and how often they eat versus formula-fed babies who may be fed predetermined amounts of food at set times.
- The composition of breast milk
The composition of breast milk changes with your baby's needs. Researchers believe these changes in breast milk may explain some of the differences in growth and size of babies.
About the scientific research
What kind of scientific review was this?
These research findings are based on three systematic reviews/meta analyses of a number of research studies. The number of study subjects ranged from 69,000 to 298,900 people, which included infants, children, adolescents and some adults. The studies reviewed were conducted in developed countries among children with no other medical condition.
Studies examined the relationship between breastfeeding and childhood obesity or between breastfeeding and obesity across all ages. Studying the effects of breastfeeding or formula feeding is complicated. There are many factors that influence the overall development of a child and many others that influence a child’s risk for obesity in later life.
The studies included here have made every effort to take into account these other factors that could have an influence, such as: birth weight, parental overweight, parental smoking, dietary factors, physical activity, socioeconomic status, age, sex, birth order and number of siblings.
What were the results of the review?
The review determined a history of breastfeeding is associated with a reduction of risk of obesity in adolescence and adult life.
Link to this review
lp S, Chung M, et al. Breastfeeding and Maternal and Infant Health Outcomes in Developed Countries. Evidence Report/Technology Assessment No. 153 (prepared by Tufts-New England Medical Center Evidence-Based Practice Center, under Contract No. 290-02-0022). AHRQ Publication No. 07-E007. Rockville, MD: Agency for Health Care Research and Quality. April 2007.
Evidence Report (Publication No. 07-E007): (
PDF file version, 3.5 MB)
About obesity