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Here's what readiness actually looks like.

When to Start Solids: Signs Your Baby Is Ready

When to start solids

Sundhedsstyrelsen (SST) recommends introducing complementary foods at around 6 months — not before 4 months completed, and not significantly after 7 months. The WHO guidance is the same: exclusive breast or formula feeding for the first 6 months, with solid foods introduced alongside milk from around 6 months onward (WHO, Infant and Young Child Feeding).

The reason for the 4-month floor isn't arbitrary. Before that point, the gut lining is still maturing, the immune system hasn't developed the capacity to handle food proteins safely, and the oral motor coordination for swallowing isn't in place (StatPearls, Complementary Feeding). Starting before 17 weeks carries a real, documented risk — not a hypothetical one.

Six months is the guideline, not a rule that applies identically to every baby. A premature baby's readiness follows their corrected age, not their birth date. And a baby who is almost 6 months but shows none of the signs below probably isn't ready yet.

Signs your baby is ready for solid food

There are three developmental signs that matter. All three should be present — not just one or two.

Sitting upright with minimal support. The baby should be able to hold their head steady and upright in a high chair without slumping forward. Support is fine, but they need to be able to maintain that position. Moving food safely from the front of the mouth to the back requires a vertical airway — a baby who can't hold their head up can't manage this without risk.

Loss of the tongue-thrust reflex. Newborns automatically push things out of their mouths with the tongue — the extrusion reflex is protective, stopping them from choking on anything that isn't milk. It fades between 4 and 6 months (ESPGHAN Committee on Nutrition, 2017). You can test it: offer a small amount of purée and watch. If most of it comes back out on the tongue, the reflex is still active. If the baby swallows it, it has largely gone.

It looks like the food is being rejected. Sometimes it is. Sometimes it's just the reflex.

Interest in food. The baby watches you eat, opens their mouth when they see food coming, reaches toward your plate. This is different from hunger — hungry babies have been communicating that since week one. What you're looking for is specific interest in what you're doing with food. According to SST, all three signs together are the reliable indicator for readiness — none of them alone is sufficient (SST, Ernæring til spædbørn og småbørn).

Signs that don't mean readiness

Night waking. A baby who starts waking again at 4 or 5 months is almost certainly moving through a developmental shift, not asking for porridge. Sleep architecture changes significantly around this age — it's one of the most common causes of regression in babies who had been sleeping in longer stretches. SST is explicit that night waking is not a reliable indicator for starting solids early.

Chewing fists. Chewing fists is what babies do. Oral exploration, teething, motor practice. It has no nutritional implications.

Seeming unsatisfied after feeds. Growth spurts happen at predictable intervals through the first year and look almost identical to a baby who has outgrown their milk supply. Usually the supply adjusts within a few days. If it consistently doesn't, talking to a health visitor is the right move — but starting solids early doesn't resolve the underlying issue, and the evidence doesn't support it as a solution (ESPGHAN Committee on Nutrition, 2017).

How to start

Offer food once a day, at a time when the baby is alert and not at either extreme — not just before a feed, not immediately after. Mid-morning works for most families. Begin with single-ingredient foods so you can track reactions: puréed cooked root vegetables, mashed banana, baby rice. SST recommends introducing vegetables before fruit, as babies exposed early to a range of vegetable flavours tend to accept more variety later (SST, Ernæring til spædbørn og småbørn).

Baby-led weaning — offering soft finger foods rather than purées from the start — is an approach many families use successfully alongside or instead of spoon-feeding. The ESPGHAN position paper on complementary feeding notes that either approach is appropriate, provided nutritional needs are met — particularly iron (ESPGHAN Committee on Nutrition, 2017).

Iron matters more at this stage than most first-feeding guides suggest. Breast milk is low in iron, and by around 6 months a baby's iron stores from birth begin to run low. SST recommends offering iron-rich foods — meat, fish, pulses, iron-fortified cereals — from the beginning of complementary feeding, not once the baby has "got the hang of" eating. Most introductory guides lead with fruit. Iron usually appears several pages later.

Frequently asked questions

Can I start solids before 6 months?

SST and the WHO both recommend not starting before 4 months completed (17 weeks), with 6 months as the target. Between 4 and 6 months is a grey zone — some babies show all three readiness signs before the 6-month mark, and some don't show them until after. The signs matter more than the calendar date.

What if my baby gags on everything?

Gagging is a normal part of learning to eat. A baby's gag reflex sits further forward in the mouth than an adult's — it's protective, and it usually resolves as they get more practice. Choking looks different: it is silent, the baby cannot cry, the face goes red. Gagging is noisy and the baby recovers immediately. Infant first-aid training is worth completing before you start solids.

Do I stop milk feeds when I start solids?

No. Breast milk or formula stays the primary source of nutrition through the first year. Solids at this stage are introduction and practice, not replacement. SST recommends maintaining milk feeds throughout the first year and not allowing solid food to significantly displace milk intake before 12 months (SST, Ernæring til spædbørn og småbørn).

Does the time of day matter?

Practically, yes. Mid-morning tends to work well — the baby is awake, not overtired, not mid-feed. Evenings are difficult: a baby who hasn't slept well will reject most things, and an unsettled late feed isn't useful data on whether a food is accepted.

Sources

• Sundhedsstyrelsen. Ernæring til spædbørn og småbørn. 2019.
• World Health Organization. "Complementary feeding." Infant and Young Child Feeding. WHO.
• Fewtrell M, et al. "Complementary Feeding: A Position Paper by the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) Committee on Nutrition." Journal of Pediatric Gastroenterology and Nutrition 64, no. 1 (2017): 119–132.
• "Complementary Feeding." StatPearls. NCBI Bookshelf. National Institutes of Health.