Feeding your baby: the complete guide

Feeding a baby in the first year involves more decisions, more uncertainty, and more sleepless nights than most parenting guides prepare you for. Breast or formula. How much. How often. Why they're spitting up again. Whether that cluster-feeding evening means something is wrong.

This guide covers the full picture — from the first feed to starting solids — with no preference for one feeding method over another. Both breast milk and infant formula are good ways to feed a baby. The research on long-term outcomes is more nuanced than headlines suggest, and the most important thing is that your baby is fed, growing, and you are coping. Everything else is detail.

Breastfeeding

Breast milk is produced on a supply-and-demand basis. The more your baby feeds, the more milk your body makes. This is why the early weeks — when a newborn feeds 8–12 times in 24 hours — are critical for establishing supply. Removing milk frequently and effectively is the main mechanism.

The first milk your body produces is colostrum: a thick, nutrient-dense, antibody-rich fluid present from late pregnancy and for the first few days after birth. Only small volumes are produced, but that matches exactly what a newborn stomach can hold (roughly 5–7 ml on day one, expanding to about 20–30 ml by day three).¹ Colostrum transitions to mature milk over days 3–5, often called the milk "coming in."

Breastfeeding offers immunological benefits — antibodies in breast milk provide passive immunity against respiratory, gastrointestinal, and other infections during the months before a baby's own immune system matures.² It also provides the ideal nutrient profile for human infants, adjusts in composition across a single feed and across months, and is protective against certain infections for the breastfeeding parent.

The most common early challenges are latch difficulties, nipple pain, concerns about supply, and engorgement. Most of these are solvable with good support. A lactation consultant (IBCLC) or a peer breastfeeding supporter can often make the difference between stopping and continuing.

One critical supplement: breastfed babies need vitamin D supplementation from birth (in the UK, 8.5–10 micrograms/day; in the US, 400 IU/day), because breast milk does not contain sufficient vitamin D regardless of the parent's own levels.³⁴

→ Full guide: Breastfeeding: the complete guide

Formula feeding

Infant formula is the only safe alternative to breast milk for babies under 12 months. Standard cow's milk-based formula is the appropriate starting point for most babies. Other types — partially hydrolysed, extensively hydrolysed, lactose-free, soy-based — exist for specific clinical indications and are not needed routinely.⁵

Formula feeding offers practical advantages: feeds can be given by any caregiver, intake is measurable, and there is no supply concern. It also requires careful preparation. Formula made with water below 70°C does not kill harmful bacteria that can be present in powdered formula — preparation temperature is a genuine safety issue, not just a recommendation.⁶

Formula-fed babies typically feed every 3–4 hours (versus every 2–3 hours for breastfed newborns) because formula takes longer to digest than breast milk. Guide amounts by age matter — underfeeding and overfeeding are both possible when a parent is guessing rather than following evidence-based volume guidance.

→ Full guide: Formula feeding: the complete guide

Breastfed vs formula-fed: what actually differs

In daily life, the most visible differences between breastfed and formula-fed babies are:

• Feeding frequency: breastfed newborns typically feed every 2–3 hours; formula-fed every 3–4 hours
• Stool colour and consistency: breastfed stools are yellow, seedy, and often very frequent in early weeks; formula stools are tan-brown, firmer, and more regular
• Gas: formula-fed babies may swallow more air, particularly from bottle nipples with fast flow rates
• Poop frequency: breastfed babies after 6 weeks can go several days between stools and still be perfectly healthy; formula-fed babies tend to be more regular

Long-term outcome differences between breast and formula are real but often overstated in popular coverage. Feeding method is one variable among many — family income, parental education, home environment, and access to healthcare all interact with feeding outcomes in ways that make isolated comparisons complex.⁷

→ Detailed comparison: Breastfed vs formula-fed babies

Reading hunger and full cues

The most important skill in early feeding is recognising when your baby is hungry and when they have had enough. Scheduled clock-feeding — every three hours regardless of cues — can work for some families after patterns emerge, but in the early weeks, feeding to cues is more reliable and better supports both supply (if breastfeeding) and appropriate intake.

Early hunger cues (feed now, before crying starts):

• Rooting — turning the head and opening the mouth when the cheek or lip is touched
• Bringing hands to mouth
• Smacking or licking lips
• Increased alertness, fidgeting, squirming
• Turning the head from side to side

Late hunger cue: crying. A crying baby is harder to latch and harder to settle onto a bottle. Feeding goes better when you catch the earlier cues.

Full cues (they've had enough):

• Turning the head away from the breast or bottle
• Slowing or stopping sucking
• Releasing the nipple
• Hands relaxing open (from fisted when hungry)
• Becoming drowsy and content

Overfeeding is more common with bottle feeding because the flow is constant and it takes effort to stop. Paced bottle feeding — holding the bottle more horizontally and allowing the baby to control the pace — helps babies self-regulate intake in the same way breastfed babies do.⁸

→ Deep dive: Hunger cues and full cues: how to read your baby

How much, how often

There is no universal answer — it depends on age, weight, feeding method, and your individual baby. But the general framework:

Newborns (0–4 weeks): 8–12 feeds in 24 hours, day and night. There is no "too often" in this window. For formula, roughly 60–90 ml (2–3 oz) per feed, increasing gradually.

1–3 months: feeds begin to space out slightly to 7–9 per day. Formula guide: approximately 120–150 ml (4–5 oz) per feed.

3–6 months: many babies settle into roughly every 3–4 hours, though breastfed babies vary considerably. Formula guide: approximately 150–180 ml (5–6 oz) per feed.

6–12 months (alongside solids): milk remains the primary nutrition source alongside solid foods until 12 months. Total daily formula volume typically plateaus around 700–900 ml.

Weight gain is the most reliable sign that intake is adequate. Breastfed babies are typically weighed at birth, day 5, day 10–14, and then at intervals recommended by your health visitor or paediatrician. Expect some weight loss in the first few days (up to 7–10% is normal); regaining birth weight by 2 weeks is the target.¹

Burping

Babies swallow air during feeds. If that air stays in the stomach, it causes discomfort, fussiness, and spit-up. Burping after feeds helps move trapped air up before it causes problems.

Formula-fed babies swallow more air than breastfed babies — partly because of the pressure dynamics of bottle feeding and partly because formula flow is harder to control than milk flow at the breast. Breastfed babies still benefit from burping, especially in the early weeks.

The three main burping holds — over the shoulder, sitting upright on the lap with chin supported, and face-down across the lap — each have their advocates. None is categorically better; what works depends on your baby.

After 3–4 months, many babies become much better at self-regulating and may not need burping after every feed. If two or three minutes of effort produces nothing, move on.

→ Deep dive: Burping: when, why, and when it doesn't matter

Spit-up vs reflux

Spit-up is normal. More than half of all babies spit up regularly in the first months of life.⁹ The lower oesophageal sphincter — the valve between the oesophagus and stomach — is immature in infants and allows stomach contents to come back up easily. This typically peaks around 4 months and usually resolves by 12–18 months as the baby spends more time upright and the sphincter matures.

A "happy spitter" — a baby who spits up frequently but is otherwise content, feeding well, and gaining weight appropriately — does not need treatment. The spit-up looks alarming (there is always more volume than you expect) but causes no harm.

Signs that warrant a call to your doctor:

• Poor weight gain or weight loss
• Projectile vomiting — forceful, shooting across the room rather than dribbling out
• Blood or bile (green/yellow) in spit-up
• Significant distress, arching, or crying during or after feeds
• Refusing feeds repeatedly
• Breathing difficulties associated with feeding

These can indicate GERD (gastro-oesophageal reflux disease) or, in rare cases, pyloric stenosis, which requires medical assessment.¹⁰

→ Deep dive: Reflux and spit-up: normal vs concerning

Hydration and wet nappies

Before solids, all hydration comes from milk. You cannot measure what a breastfed baby takes in at each feed, but you can count wet nappies — and that count is the most reliable indicator of adequate intake available to parents at home.

After day 5, the target is 6 or more heavy wet nappies in 24 hours. Pale or clear urine; noticeably heavier nappy than a dry one. This target applies whether you are breastfeeding or formula feeding.

If the count drops below 6, or if you see dark amber or pink-stained urine beyond day 3, that warrants a call to your midwife, health visitor, or GP.¹¹

→ Deep dive: Wet nappies and hydration: how to read pee output

When solids enter the picture

Solid foods are not recommended before 4 months, and the NHS, AAP, and WHO guidance aligns on waiting until around 6 months when possible.¹² Before that point, the gut lining is not mature enough to handle most foods safely, and the swallowing reflex is not coordinated for solid textures.

Signs of readiness (usually around 6 months): sitting with minimal support, good head control, showing interest in food, and the extrusion reflex (pushing food out with the tongue automatically) has diminished.

Starting solids does not replace milk feeds immediately — milk remains the primary nutrition source through the first year. Solids are an addition, not a replacement, until 12 months.

When to call a doctor

Most feeding concerns are normal variations — but some signs need prompt medical attention.

Seek urgent or emergency care if your baby:

• Has projectile vomiting that occurs consistently after every feed (possible pyloric stenosis, especially if the baby is 2–8 weeks old and male)
• Has blood in the stool
• Is not breathing normally
• Is limp and unresponsive

Feeding problems are among the most common reasons for GP and health visitor calls in the first weeks — you are not bothering anyone. These are the questions these services exist to answer.

Sources

1. NHS. "Breastfeeding: the first few days." NHS, 2024. https://www.nhs.uk/conditions/baby/breastfeeding-and-bottle-feeding/breastfeeding/breastfeeding-the-first-few-days/
2. Victora CG, et al. "Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect." The Lancet 387(10017), 2016. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)01024-7/fulltext
3. NHS. "Vitamins for children." NHS, 2024. https://www.nhs.uk/conditions/baby/weaning-and-feeding/vitamins-for-children/
4. American Academy of Pediatrics. "Vitamin D Supplementation for Infants." HealthyChildren.org, 2023. https://www.healthychildren.org/English/healthy-living/nutrition/Pages/Vitamin-D-Supplementation.aspx
5. NHS. "Types of infant formula." NHS, 2024. https://www.nhs.uk/conditions/baby/breastfeeding-and-bottle-feeding/bottle-feeding/types-of-infant-formula/
6. NHS. "Making up infant formula." NHS, 2024. https://www.nhs.uk/conditions/baby/breastfeeding-and-bottle-feeding/bottle-feeding/making-up-infant-formula/
7. Victora CG, et al. "Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect." The Lancet 387(10017), 2016. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)01024-7/fulltext
8. NHS. "Bottle feeding: paced feeding." NHS, 2024. https://www.nhs.uk/conditions/baby/breastfeeding-and-bottle-feeding/bottle-feeding/paced-bottle-feeding/
9. NHS. "Reflux in babies." NHS, 2024. https://www.nhs.uk/conditions/reflux-in-babies/
10. American Academy of Pediatrics. "Reflux (GER and GERD) in Infants." HealthyChildren.org, 2023. https://www.healthychildren.org/English/ages-stages/baby/feeding-nutrition/Pages/Reflux-GER-and-GERD-in-Infants.aspx
11. NHS. "Dehydration in babies." NHS, 2024. https://www.nhs.uk/conditions/dehydration/
12. NHS. "When can I give my baby solid food?" NHS, 2024. https://www.nhs.uk/conditions/baby/weaning-and-feeding/when-can-i-give-my-baby-solid-food/