Will early introduction of solid foods increase my baby's risk of obesity?

Formula-fed infants who are fed solid foods before 4 months of age are at greater risk for becoming obese, studies show. The reason why is unclear. Some studies suggest the risk is tied to metabolic factors, others point to changes in the microbiome of the infant’s gut, and still others suggest the risk is related to behavioral factors. One thing is clear: The risk of obesity is indeed higher when solid foods are started early—that is, before 4-6 months of age.

Childhood Obesity by the Numbers

Childhood obesity is a global epidemic and a critical public health challenge. Although the risks are well-recognized among school-age children and adolescents, until recently, less attention has been paid to overweight and obesity during infancy and toddlerhood. 

The Centers for Disease Control and Prevention (CDC) reports an estimated 21.2 percent of 12-19 year olds is obese, and about 20.3 percent of 6-11 year olds. Among children ages 2–5, the prevalence of obesity is about 13.4 percent. It may be that steps to reduce the prevalence of obesity in younger children—including waiting to introduce solids no sooner than 4 months of age—will help reduce their risk of obesity beyond infancy.

Starting Solids

Research shows that parents and caregivers should hold off on feeding their infants solid foods until at least 4 months of age—or even 6 months, as recommended by the American Academy of Pediatrics (AAP), World Health Organization (WHO), and other leading health authorities for breastfed infants. Waiting until 4-6 months helps to ensure that your infant’s digestive system is mature enough to handle solid foods. 

Parents may be tempted to introduce solid food earlier, thinking they will better “fill up” their babies, or interpreting their child’s curiosity about table foods as readiness for it. In fact, infants need to meet several developmental milestones before starting solids should occur:

  • Your baby should be able to sit up well without help.
  • Your baby should be able to chew and swallow. Their tongue-thrust reflex should be gone.
  • Your baby should be interested in food, and able to grasp it (developing a pincer grasp).

Remember, when it comes to starting solid foods, you’ll want to value quality over quantity. For several weeks, you can focus on the process of introducing new foods, helping your child have a positive first experience, and building acceptance to nutrient-dense, healthy foods. For example, a teaspoon or two of avocados is worth more than a handful of oat cereal. Staying away from the “junk food” and juice, while helping to build your baby’s taste for healthy food, will go a long way to helping lower their risk of obesity throughout childhood.

For more about your child’s readiness for solid foods, and best first foods to choose, read this. 

Last updated March 31, 2021

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