Baby Symptoms & Conditions

Rapid Weight Gain In Babies

Could baby be gaining too much weight? We've got the scoop.

What is rapid weight gain for a baby?

Babies gain weight at a remarkable rate. By three to four months, many will have doubled their birth weight. Breastfed babies tend to gain weight at a different rate than formula-fed babies. After a few months, though, the rate of weight gain in all babies starts to decrease, slowing even further after age one. Growth rates continue to fluctuate for toddlers, though, so don’t be surprised if your two-year-old seems to have outgrown a 3T in what seems like overnight.

What could be causing my baby’s rapid weight gain?

Most likely, your child’s weight gain is part of his normal growth. Your doctor should be keeping tabs on and monitoring his growth to determine whether he’s adding on the ounces at a healthy level. They’ll typically measure head size, length and overall weight at checkups to make sure he’s staying on track. The most obvious reason for too much weight too soon is overeating, but don’t get out the diet books just yet. Weight gain can also occasionally be attributed to certain medications and, in rare instances, even a hormonal condition.

When should I bring my baby to the doctor with rapid weight gain?

Being aware of weight is important at any age, but note that babies who gain weight quickly in the first six months of life have a greater chance of being obese by age three, according to a Harvard Medical School study. Your doctor will measure your baby or toddler’s size at each visit and compare it with growth charts (which show average growth rates for kids). But if you’re concerned, you can always make an appointment just to do a weight check. (After all, your doctor’s the one with that handy baby scale.)

What should I do to treat my baby’s rapid weight gain?

No one wants to deprive a hungry baby, so always feed him when he’s looking for the breast or bottle. Babies and toddlers are generally well-tuned-in to their hunger levels, so follow their signals when it comes to the amount of food they should be eating. If you’re worried about your toddler’s rate of weight gain, start by eliminating the juice and high-sugar snacks, and emphasize quality foods (fruits, vegetables, lean proteins, whole grains) over quantity.

By Wendy Sue Swanson, MD, FAAP, pediatrician with Seattle Children's Hospital, Everett Clinic