The Bottle Makes the Baby

Babies Feeding from Large Bottles Eat More, Gain More Weight
June 16, 2016

Admit it. At least once in your life, you have eaten a little more than you needed to. Obviously, eating too much is not ideal for our health, but everyone does it sometimes, and there are worse vices than eating an extra slice of pie, pizza or Thanksgiving turkey every once in a while.


We all have our reasons for overeating: maybe because sushi is just too good to put down, or maybe we go overboard on dinner because we haven’t had anything to eat all day or maybe it’s just a special occasion. 

Frequently overeating, however, can be a major problem, contributing to obesity, which is a risk factor for diabetes and heart disease. Now, new research from UNC and Duke Schools of Medicine is showing that we may start overeating at a much younger age than we thought, before we are even able to feed ourselves.

According to a new paper published in the journal Pediatrics, infants fed from a large bottle before they are two months old show greater weight gain and greater weight-to-length ratio than children of the same age drinking from smaller bottles.

Dr. Charles Wood, a pediatrics instructor at UNC School of Medicine and lead author of the study says that weight gain at such a young age could be a risk factor for obesity.

According to the National Institutes of Health, more than one-third of adults and one-sixth of adolescents are obese. Previous research has shown that people in those age groups tend to eat and drink more when eating from large plates or drinking from large containers.

This research shows that this effect is prevalent even at a very young age. The researchers followed 379 bottle-fed infants from between their two-month and six-month pediatrician’s visits. The infants’ parents brought their bottles to the six-month visit and demonstrated how much they filled their bottle.

At the time of the six-month visit, infants drinking formula out of a greater than six ounce bottle had gained almost half a pound more than the babies fed with smaller bottles.


Obviously, the infants themselves are not in total control control of how much they eat as they are reliant on a parent to fill the bottle give it to them. It makes sense then, that the same psychology that drives adults to eat more when they have a bigger plate would drive them to give more milk or formula to an infant when they have a bigger bottle. 

Even though we may know that a baby is supposed to consume a certain number of ounces at every feeding, if that volume of formula only takes up a third of the bottle, it might not appear like the baby is getting enough. That idea might also make us ensure the baby drinks every last drop, even if he or she is not particularly hungry. 

Wood says it is important to learn the child’s cues for when he or she is full or hungry. Having that understanding and keeping a close eye on the baby during feeding can help parents know when the baby has had enough and keep them at a healthy growth rate.

The researchers will continue to study how infant feeding habits relate to their risk for obesity later in life, as Wood and his colleagues say the science of infant growth is extremely complicated. They are confident, however, that keeping bottle size and the baby’s fullness cues in mind when feeding are part of the puzzle to help children grow up at a healthy weight.

—Daniel Lane

Daniel Lane covers science, medicine, engineering and the environment in North Carolina.