What Causes Babies to Gain Weight?

How much a baby weighs is a general indicator of her health. Feeding your baby either breast milk or formula will help her grow; however, the Cooperative Extension at Clemson University in South Carolina reports that normal weight gain during infancy may lower the risk for being overweight or obese later in life 1. Studies suggest that breastfed babies don’t gain weight as quickly as formula-fed babies which may actually be a healthy thing.

Infant Formula

Although the Food and Drug Administration regulates all brands of infant formulas sold in the United States for nutritional requirements, research suggests that cow’s milk formulas may lead to babies gaining more weight. In an article written by NPR health policy correspondent Patti Neighmond, Dr. Nicolas Stettler, a pediatrician at Philadelphia’s Children’s Hospital, points out that formula-fed babies often gain weight quickly during the first months of life. Weight gain early on increases the risk of becoming overweight later in childhood and, like adults, obese children can suffer more health problems.

Breast Milk

While most babies double their birth weight by the time they are 4 months old, breastfed babies don’t gain weight as quickly as babies who are formula-fed. According to the American Pregnancy Association, studies show that infants begin to grow at different rates after 4 months depending on whether their nutritional needs are met with formula or breast milk 3. Babies who are breastfed normally stop nursing once they feel full. Breast milk is also easier for babies to digest than some infant formulas 1.

Cow’s Milk

The American Academy of Pediatrics advises parents against feeding infants regular cow’s milk, especially during the first year of life. Cow’s milk doesn’t have the right amounts of the essential nutrients and healthy fats that contribute to a baby’s growth. Since whole cow’s milk has more calories per ounce than breast milk, your baby can gain weight if he overfeeds and yet not get the full nutrition he needs. Drinking too much cow’s milk may also decrease your baby’s appetite for other foods once you start adding solid foods in his diet. Poor nutrition can affect his weight, health and normal development.

Family History

Your baby may be at risk for being overweight if weight problems and obesity run in the family. The Harvard School of Public Health reports that both a baby’s genes and her environment can affect whether she will gain too much weight 5. Studies have linked higher birth weight to obesity in childhood and adulthood. Data suggest that gaining too much weight during pregnancy or already being overweight or obese at the onset of pregnancy increases the risk of a baby becoming obese by age 3. Studies also suggest that babies who gain weight quickly during the first 3 or 4 months after birth are at a higher risk for obesity later on.