How Does Bottle Feeding Increase the Risk of Obesity?

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Too much weight gained in the early days and weeks is linked to obesity in childhood and adulthood. Obesity is linked to a variety of health issues, including diabetes, heart disease, and cancers. The U.S. Surgeon General’s 2011 Call to Action to Support Breastfeeding cites a 32% increased risk of obesity if babies aren’t breastfed, and a 4% reduction in risk for every month a baby breastfeeds! In a study of families where one sibling was breastfed and one sibling wasn’t, the breastfed sibling was less likely to reach the family BMI average — a difference of more than 13 pounds for a 14-year-old child of average height.

Why do bottle-fed babies gain more weight than exclusively breastfed babies who grow at a healthy rate? Research shows there is a difference in weight gain even when fed breastmilk by bottle! Babies fed at the breast won’t nurse when they’re full; babies fed with a bottle have to swallow or choke, and learn to ignore their fullness cues if their caregiver makes them finish the bottle.

Formula feeding and scheduled feedings (following the clock instead of the infant’s hunger cues) are linked to extra weight gain in the early months. One study says that every 3.5 ounces a baby gains in the first week of life increases his risk of being obese by 28%!


  • At an average feeding, formula-fed babies consume more per feed than breastfed babies, and the difference in volume increases as the baby grows:
    • 49% more at 1 month
    • 57% more at 3 months
    • 71% more at 5 months

  • Despite having fewer feedings throughout the day, formula-fed babies drink more per day!
    •15% more at 3 months
    • 23% more at 6 months
    • 20% more at 9 months
    • 18% more at 12 months

Breastfeeding encourages healthy weight gain

  • When breastfeeding, the flow of milk varies. This lets baby’s tummy realize it’s full sooner than when fed with a steadily flowing bottle.

  • When breastfeeding, the amount of fat increases in the milk as the feed continues. The higher fat content may tell baby that he’s finished his meal.

  • When breastfeeding, baby can control how much he drinks; he will unlatch and turn away when he’s full. This self-regulation follows his fullness cues, and mom learns to trust when baby says he’s done, even when solids are introduced. When bottle feeding, the caregiver may encourage baby to finish the bottle, even if baby’s tummy is full.

  • Breastmilk components encourage healthy nutrient use, metabolism, and appetite. For example, the hormone leptin controls appetite and body fat, and encourages healthy, normal weight.

Babies fed expressed breastmilk by bottle gain excess weight

A recent study on 1,899 babies found that for every 10% increase in breastmilk feedings by bottle, babies gained an extra 3.6 g per month if they received between 33%-66% of the feeds by bottle. If more than 66% of their feeds were by bottle, the babies gained an extra 8% per month than breastfed babies!

What should moms do if their babies use a bottle?

Regardless of what’s inside the bottle, babies should be in control of the feed. The Paced Bottle Feeding Method lets the baby suck to get milk, so he doesn’t get a steady flow. Pausing during the feeding lets baby’s tummy recognize that it’s full, and the caregiver learns to recognize baby’s signs of being full.

If baby has gotten used to receiving bottles that contain more milk than he needs, the caregiver can gradually reduce the amount of milk in the bottle and/or not encourage baby to finish drinking the entire amount when baby shows he’s had enough.

How is your baby gaining weight?

The current CDC growth charts for boys and girls use the data from the World Health Organization growth chart. The WHO charts reflect growth patterns among children in six countries. These children were predominantly breastfed for at least 4 months and still breastfeeding at 12 months. Unlike the old CDC charts that showed typical growth in a certain period, these new charts are standards for optimal growth.

Is your pediatrician using the correct growth chart for your baby?