If you’ve ever found yourself crying into a bottle of formula—or sobbing during a 3 a.m. nursing session while Googling “how to increase milk supply”—you’re not alone.

One of the most common questions I get from new parents is:
“How do I know if my baby is getting enough milk?”

Whether you’re breastfeeding, using formula, or somewhere in between, the goal isn’t perfection. The goal is a thriving baby. And yes—your baby can absolutely thrive no matter how they’re fed.

This guide will help you understand:

• Signs your baby is getting enough breast milk or formula

• What normal weight gain looks like

• When to worry about feeding

• And how to tell if your baby is truly thriving

Universal Signs Your Baby Is Doing Well

No matter how your baby is fed, these are the green flags pediatricians look for:

Wet Diapers

• At least 6 wet diapers per day by day 5 of life

• Pale or clear urine means baby is well-hydrated

Poops

• At least one bowel movement per day in the first month

• Color should change from black meconium to yellow seedy (breastfed) or soft brown/green (formula-fed) by day 5

Weight Gain

• Regains birth weight by 10–14 days of life

• Gains approximately 0.5–1 ounce per day in the first 3 months

Baby Behavior

• Baby wakes up on their own to feed

• Appears satisfied and content after feeding

• Alert, making eye contact, and responsive to voices

If you’re seeing these signs, your baby is likely getting exactly what they need.

Signs a Breastfed Baby Is Getting Enough

Breastfeeding comes with its own uncertainties, especially since you can’t measure ounces. Here’s what tells me as a pediatrician that your breastfed baby is doing well:

• Baby latches deeply with lips flanged and no nipple pain after the first week

• You can hear or see swallowing during feeding

• Feeds 8–12 times in 24 hours in the early weeks

• Poops are mustard yellow and seedy by day 5

• Baby is calm and content after feeds

Cluster feeding (frequent feeding in short bursts) is completely normal—especially during growth spurts.

Signs a Formula-Fed Baby Is Getting Enough

Formula-fed babies are often easier to track by ounces, but here’s what to watch for:

• Feeding every 3–4 hours

• Drinking about 2–2.5 ounces per pound of body weight per day (an 8-pound baby might take 16–20 oz/day)

• Steady weight gain, around 1 oz per day in early infancy

• Soft, regular bowel movements that are brown or green

• Appears calm and satisfied after feeds

If your baby seems unusually fussy, has bloody stool, or severe spit-up or eczema, talk to your pediatrician—it may be a formula intolerance or milk protein allergy.

Common Feeding Myths (That Cause Way Too Much Guilt)

Let’s debunk a few myths right now:

• “Breastfed babies are always healthier.” → Not necessarily. Plenty of formula-fed babies are thriving.

• “Formula causes obesity.” → Not true. Overfeeding habits—not the formula itself—are more important.

• “I failed because I needed to supplement.” → No, you didn’t. You’re feeding your baby. That’s a win.

Fed is best. Thriving is the goal. Guilt is optional.

When to Call Your Pediatrician

While most feeding variations are normal, contact your doctor if:

• Baby has fewer than 6 wet diapers per day after day 5

• Baby hasn’t regained birth weight by 2 weeks

• Baby is lethargic or too sleepy to feed

• Baby is vomiting (not just spitting up)

• You see blood or mucus in stool

• Something just feels “off” to you

You don’t need permission to trust your gut.

Final Thoughts: You’re Doing Better Than You Think

Feeding your baby is not a competition. It’s a relationship—one that changes, adapts, and grows.If your baby is gaining weight, feeding regularly, and seems content, they are doing great.

You are not failing.
You are feeding.
You are learning.
You are showing up.

That’s what matters most.

Watch the Full Video

Want this explained with stories, visuals, and real-life examples?
Watch my YouTube video: “Breastfeeding vs. Formula: Why Fed Is The Real Win”

Need support or reassurance?
Follow me on Instagram @DrLeslieTreece for daily tips, judgment-free feeding advice, and the occasional coffee-fueled rant.