What’s the Difference Between Breastmilk and Formula?

It's one of the first big decisions you'll make as a new mom: help that baby to latch, or pop open a tiny formula bottle? (For some women, there is no choice— their body or baby makes the decision.) But how exactly does nature's milk differ from the store-bought stuff, and what does it mean for you and your little? We spoke with family physician Rallie McAllister, MD, MPH, coauthor of The Mommy MD Guide to Your Baby’s First Year (and a mom of three who fed her babies a mix of breastmilk and formula) about the pros and cons of each. How to feed your little is a super personal decision—we’ll milk cheers whichever plan works out for you.

The Perks of Breastmilk

Got a bump? Odds are you've heard the words ‘breast is best.’ The American Academy of Pediatrics recommends women feed their babies breastmilk (a power combo of carbs, protein and fat doctors like to call 'liquid gold') exclusively for the first six months of baby's life because it performs some high-quality magic: breastmilk contains immune-boosting antibodies that protect baby from getting sick, it can lower his or her risk of obesity, diabetes, and allergies, and breastfeeding—even for just two months—has been shown to reduce a baby’s risk of SIDS (Sudden Infant Death Syndrome) by half. (The option to pop baby on the breast whenever and wherever hunger strikes can be key to avoiding sudden meltdowns, too.) Moms also score big from breastfeeding: churning out milk burns an extra 500 calories or so a day, triggers a chemical release of oxytocin that helps you relax, and can reduce your risk of breast cancer, ovarian cancer, and type 2 diabetes.

The Hold-Up

Reality check: as perfect as breastmilk is, 60 percent of moms don’t breastfeed for as long as they’d like to. Turning into an all-day-cafe for your baby can be super time consuming and painful for some women (hello latch issues, clogged ducts, cracked nipples, and infections like mastitis). And while that physical tie to baby offers a next-level bonding experience, it also means you're on the clock more than your co-parent. (Around 3 a.m., having boobs can start to feel super unfair.) For those heading back to work, there’s the often hefty cost of a pump, storage bags, nursing bras and pads to tally up, plus the stress of trying to pump between meetings (or—gulp—leaking in the middle of one).

Food for Thought

Sharing even just a little bit of that liquid love is better than none at all, says McAllister. Colostrum (the super thick, golden-colored milk that comes in the first few days after delivery) creates a powerful coating on baby’s stomach and intestines to ward off germs, helps prevent jaundice, and can make it easier for baby to pass that tar-like first poop called meconium.

The Perks of Formula

Let’s get this out of the way: “Infant formula is safe and totally nutritious,” says McAllister. All formula (which is essentially cow’s milk that's been tweaked to mimic breastmilk) sold in the United States has to meet strict standards set out by the FDA—meaning you never have to worry if baby’s getting enough nutrients critical to his or her growth, regardless of the brand. (Formula fed babies don’t have to supplement with Vitamin D like breastfed babies do, either.) Some babies sleep better after a bottle of formula, which takes longer to digest than breastmilk and can keep them full for longer, and if your little has a dairy allergy or is struggling with reflux, special formulas can help ease their belly woes. A priceless perk: bottle feeding can help equalize parenting duties and gives your co-parent a chance to bond with baby, too, says McAllister. (Ideally during that 3 a.m. shift.)

The Hold-Up

There’s no getting around it—baby formula just doesn’t pack the magic, disease-fighting antibodies breastmilk contains. And because formula takes longer to digest, bottle-fed babies may battle more gas and constipation. Formula can be costly (some organic brands may set you back over $100 a month), meanwhile washing and sterilizing bottles can feel like a full-time job.

Food for Thought

If you can’t breastfeed, or find it’s not for you, your baby will be better than ok. “Baby formulas are a completely acceptable, doctor-approved, and time-tested alternative to breastfeeding. Two out of three moms give their babies formula in baby’s first year,” says McAllister. (No research shows formula-fed babies take a hit when it comes to health or achievement in the long run, either.) At the end of the day, if your baby is fed and snuggled, you're both doing great.