The infant feeding schedule:

Why--breast or bottle--babies benefit from being fed "on demand"

© 2008 - 2014 Gwen Dewar, Ph.D., all rights reserved

What’s the best infant feeding schedule?

For generations, Western “baby experts" have advised parents to feed their babies at regularly-spaced intervals of 3- or 4-hours. Today, official medical recommendations have shifted in favor of feeding on demand.

That’s probably a good thing, because the timed-interval infant feeding schedule is not dictated by physiology or what’s best for babies.

Research suggests that many babies are better off if they are permitted to regulate their own feeding bouts. In fact, as I note below, it's even possible that scheduled feeding -- for breastfed and bottle-fed babies alike -- has a negative impact on cognitive development (Iacovou and Sevilla 2013).

Unfortunately, parents don’t always get this message. The time-interval infant feeding schedule has become culturally entrenched, and some hospitals have been slow to adopt the sorts of practices--like rooming in--that promote feeding on demand (e.g., Kersting and Dulon 2001).

This article reviews the evolutionary, cross-cultural, and medical evidence in favor of frequent, baby-initiated feedings. As noted below, the evidence supports the following conclusions:

  • New mothers are more likely to establish an adequate milk supply if they breastfeed frequently and on demand
  • Newborns should be fed frequently and whenever they show signs of hunger—ideally, before they begin to cry
  • It's a good idea to let the baby's interest--not the clock--determine when a breastfeeding session is over.
  • "On demand" infant feeding schedules permit babies to adjust their intake in response to natural variations in breast milk quantity and quality
  • Infants breastfed on demand may benefit from higher quality breast milk and fewer digestive problems
  • Infants (of any age) breastfed on demand may experience less stress and pain
  • Infants fed on demand may take more naps
  • Moreover, women who breastfeed their newborns on demand are more likely to continue breastfeeding after 1 month.

For these reasons, both the World Health Organization (WHO) and the American Academy of Pediatrics (APP) now recommends that breastfeeding mothers follow a baby-initiated infant feeding schedule.

Formula and the infant feeding schedule

What about formula feeding? There is growing concern among some researchers that babies who feed from bottles may be at increased risk for overfeeding.

For example, in one study of 1250 American infants, researchers found that bottle-feeding in early infancy was associated with a tendency to eat everything on offer. The more frequently babies drank from bottles during the first 6 months, the more likely they were in later months to drink everything from a bottle or cup given to them (Li et al 2010).

A smaller study conducted in the United Kingdom reports similar results (Brown and Lee 2012), and keep in mind -- the results were the same for both formula-fed babies and babies who consumed breast milk. It was the bottle, not the specific contents of the bottle, that seemed to matter.

It's not yet clear what this means. Infants can extract milk more quickly from a bottle than they can from a breast. Perhaps the fast pace leads to consuming more during a feed, and babies being accustomed to taking in bigger meals.

This might sound like an argument against feeding such babies on demand. Left to their own devices, won't they consume too much?

But studies suggest that both breastfed (Woolridge and Baum 1992) and formula-fed (Fomon et al 1975) infants adjust their intakes in response to changes in the calorie content of their milk or formula, consuming less when meals are rich.

Given this, and the apparent benefits of feeding babies on cue (see below), it seems prudent for parents of formula-fed babies to begin by feeding on demand, and then consult with their pediatricians about their babies' weight gain over time.

The infant feeding schedule in evolutionary perspective

Mammals are named for their milk-secreting mammary glands, and mammal babies everywhere begin life on a diet of milk. But not all milk is alike, and different species follow different infant feeding schedules.

Survey the world of mammalian infant care, and you’ll discover two major feeding strategies: the spaced feeders and the continual feeders.

Spaced feeders “park" or "cache" their young in nests and leave them there—unattended—for hours at time. Mom uses her time away to forage. The kids must wait for long intervals between feedings. But they don’t go hungry: Spaced feeders have evolved high-fat, high-protein milk. And the babies are designed to suck fast and furious when they get the chance.

A good example of a spaced feeder is the rabbit, which produces milk that is 18.3% fat and 13.9% protein (Jenness 1974).

By contrast, continual feeders stay with their babies at all times. Whether they follow their moms around on foot (like cows) or get carried (like monkeys), kids stay in close contact with Mom. They get fed more frequently than spaced feeders do, and they tend to initiate feedings. Consistent with their high-frequency infant feeding schedule, they suck at a more leisurely rate. Their milk is less caloric, more dilute. Cow milk is typically 3.7% fat and 3.4% protein (Jenness 1974).

So what about humans?

In some modern industrial societies, humans act like spaced feeders. Babies are “parked" in cribs or cradles and get fed after intervals of 3-4 hours. But were we designed for this strategy? The answer is no.

Humans belong to the order Primates, a group that includes prosimians, monkeys and apes. A few—mostly nocturnal, prosimian species—are spaced feeders (Teilden and Oftedal 1997).

But most—including our closest living relatives, the gorillas, chimpanzees, and bonobos—-are continual feeders.

And the proof is in our milk: Compared to the milk of spaced feeders, human milk is relatively low in fat (3.8%) and protein (1%), and human infants suck slowly when they feed.

So the composition of our milk gives us away. We’re meant to be continual feeders. (Click here for a more detailed account of the nutrients and calories in human breast milk.) But though human milk is comparatively dilute, this doesn’t mean that human milk is everywhere and always the same.

Breast milk composition may vary significantly among individual women, and the same woman may experience significant fluctuations in her milk quality over time.

And--most interesting for our discussion here--that fat content of human milk increases when babies feed more frequently.

Human milk quality improves with frequent feedings...and volume of intake

International studies show that the more frequently a woman breastfeeds, the higher the fat content of her milk (Prentice and Prentice 1988; Prentice et al 1981; Jackson et al 1988; Daly et al 1993).

Other factors associated with higher fat content include the volume of intake at previous feed (how much milk the baby ingested at the last feeding) and volume of intake at the current feed (Woolridge 1995).

Volume of intake is important because the highest fat milk comes from soft, apparently empty breasts.

When a baby begins feeding from a full breast, the milk she receives (“foremilk") is relatively low in fat. Fat content increases as the breast empties.

For this reason, it’s important not to force babies to switch breasts before they’ve had their fill. Premature switching can rob the baby of the higher-fat hindmilk associated with the latter part of a feed (Woolridge and Fisher 1988).

So it's wise to let the baby decide when it’s time to switch—-if ever. Some babies may nurse from one breast exclusively during a feeding session. And that’s fine.

These discoveries suggest that women can improve the quality of their breast milk by feeding frequently and on demand.

And quality matters. When milk quality is low, babies need to consume more of it to get the same caloric benefit. Babies vary in their ability to suck quickly and efficiently. If access to the breast is limited—as it is on a regimented infant feeding schedule—some babies may not get enough to eat (Woolridge 1995).

Low-quality milk can cause other problems as well. As breastfeeding expert Michael Woolridge (MD and PhD) has pointed out, low-fat milk can contribute to colic, vomiting, diarrhea, and flatulence in infants (Woolridge 1995).

So--from the standpoint of our evolutionary heritage and the quirks of human milk production--it appears that frequent feedings are better for babies. The regimented, once-every-four-hours infant feeding schedule isn't well-suited to the human infant's needs.

The hunter-gatherer infant feeding schedule...and beyond

How frequently should babies be nursed?

There is probably no single, “right" answer to this question. But the practices of contemporary hunter-gatherers--whose life-ways are probably most similar to those of our ancestors--are strikingly different from those of industrial Westerners.

Among the !Kung San of South Africa, the traditional pattern is for babies to be fed about 4 times an hour. Feeding bouts are brief, lasting only 2 minutes or so (Konner 2006). And nursing continues—on demand—throughout the night. The !Kung might represent the extreme end of feeding frequency, but other hunter-gatherer groups—from South America to the Philippines—follow a similar pattern, nursing at least twice an hour (Konner 2006).

And it’s not just hunter-gatherers. In a recent, cross-cultural survey sampling 48 non-industrial societies--including nomadic pastoralists and settled agricultural peoples--demand feeding was the rule in every society for which information about the infant feeding schedule was available (25 out of 25; Severn Nelson et al 2000).

It seems likely that frequent, infant-initiated nursing has been the normal human pattern for over 99% of human history.

Why it matters

Skeptics might argue that milk fat concentrations and hunter-gatherer practices are irrelevant as long as babies thrive. Babies around the world have adapted to a variety of feeding styles, and, despite concerns that scheduled feedings may not serve babies well during growth spurts, there isn't yet any evidence that scheduling hinders the growth of healthy, full-term babies (Saxon et al 2002).

But whether or not scheduled feeding poses problems for energy intake, there are other considerations. Research suggests that feeding on demand has psychological benefits.

Less pain, less stress, and smarter kids?

Food is known to have a calming effect on babies, even if they are not especially hungry.

Newborns cry less and show signs of reduced pain when they receive small amounts of milk, formula, or sucrose (see review by Shaw et al 2007; also Blass 1997a; Blass 1997b; Blass and Watt 1999; Barr et al 1999). The act of suckling is itself an analgesic (Blass and Watt 1999), and breastfeeding may be a painkiller and stress-reducer.

When some newborns were randomly assigned to be breastfed during a painful blood collection procedure, the breastfeeding babies experienced far less distress than did controls (Gray et al 2002).

Breastfeeding babies cried for only 4% of the total procedure time, as opposed to 43% for controls. Grimacing was also markedly reduced (8% v. 50%), and breastfeeding babies showed less of an increase in heart rate (6 beats per minute v. 29 beats per minute).

Interpreting this study is difficult, because breastfeeding babies, but not control babies, received skin-to-skin contact, which is also known to reduce pain.

However, the authors of this study believe that breastfeeding is a more effective analgesic than skin-on-skin contact alone. When the authors performed a similar experiment on the effects of skin-on-skin contact, babies grimaced more than did the breastfeeding babies (Gray et al 2000; Gray et al 2002).

The authors also note that babies who are held without being fed tend to get frustrated, and require much more time to settle down (Gray et al 2002).

And what might happen to a baby who finds her signals for food are routinely ignored?

While I've found no studies that bear directly on this question, a large variety of studies suggest that sensitive, responsive parenting contributes to secure attachment relationships and better child outcomes.

There is also intriguing research regarding cognitive development.

In what is perhaps the largest study yet to investigate the effects of an infant feeding schedule, Maria Iacovou and Almudena Sevilla (2013) tracked the development of more than 10,000 British children -- breastfed and bottle-fed alike -- from birth to age 14.

There were no experimental manipulations. The researchers merely noted whether babies had been fed on schedule or on demand, and then followed their cognitive and academic progress. And the results favored feeding on demand:

At every age, kids who'd been subjected to an infant feeding schedule performed more poorly on standardized tests. Moreover, their IQs were, on average, 4.5 points lower.

Correlation doesn't prove causation, of course, but the results remained much the same after controlling for a variety of potential confounds, including parents' education levels, economic factors, health, breastfeeding, maternal smoking, and the children's exposure to negative discipline tactics.

The bottom line

Human breastfeeding seems designed to operate on an on-demand basis. When babies determine the timing and duration of their feeds, they are more likely to get what they need. Breast milk production increases or decreases in response to the baby's demand. Breast milk quality may improve.

If breastfeeding evolved as an "on demand" operation, mightn't babies have evolved the psychology to go with it? It's speculative, but the evidence is consistent. Feeding reduces pain and stress.

Moreover, a recent study hints that feeding on demand leads to better cognitive outcomes -- for breastfed and bottle-fed babies alike.

References: The infant feeding schedule

Barr RG, Pantel MS, Young SN, Wright JH, Hendricks LA, Gravel R. 1999. The response of crying newborns to sucrose: is it a “sweetness" effect? Physiol. Behav 66: 409-417.

Blass EM. 1997a Milk-induced hypoanalgesia in human newborns. Pediatrics 99: 825-829.

Blass EM. 1997b. Infant formula quiets crying newborns. Journal of Dev Behavioral Pediatrics. 18:162-165.

Daly SE, DiRosso A, Owens RA and Hartmann PE. 1993. Degree of breast emptying explains fat content, but not fatty acid composition, of human milk. Exp Physiol 78: 741-755.

Disantis KI, Collins BN, Fisher JO, and Davey A. 2011. Do infants fed directly from the breast have improved appetite regulation and slower growth during early childhood compared with infants fed from a bottle? Int J Behav Nutr Phys Act. 8:89.

Fomon SJ, Filmer, Jr., JA, Thomas LN, Anderson TA and Nelson SE. 1975. Influence of formula concentration on caloric intake and growth of normal infants. Acta Pediatrica Scandinavica 64: 172-181.

Gray L, Miller LW, Philipp BL, Blass EM. 2002. Breastfeeding is analgesic in healthy newborns. Pediatrics 109: 590-593.

Gray L, Watt L, Blass EM. Skin-to-skin contact is analgesic in healthy newborns. Pediatrics 105(1).

Iacovou M and Sevilla A. 2013. Infant feeding: the effects of scheduled vs. on-demand feeding on mothers' wellbeing and children's cognitive development. Eur J Public Health. 23(1):13-9.

Illingworth RS, Stone DHG, Jowett JH and Scott JF. 1952. Self-demand feeding in a maternity unit. Lancet 1: 683-687.

Jackson DA, Imong SM, Silpraset A, Preunglumpoo Ruckphaopunt S, Williams AF, Woolridge MW, Baum JD, and Amatayakul K. 1988. Circadian variation in fat concentration of breastmilk in rural Northern Thailand. British Journal of Nutrition 59: 365-371.

Jenness 1974. Biosynthesis and composition of milk. Journal of investigative dermatology. 63: 109-118.

Kersting M and Dulon M. 2001. Assessment of breastfeeding promotion in hospitals and follow up survey of mother-infant pairs in Germany: The Su-Se study. Public Health Nutrition 5(4): 547-552.

Konner M. 2005. Hunter-gatherer infancy and childhood: The !Kung and others. In: Hunter-gatherer childhoods: Evolutionary, developmental and cultural perpectives. BS Hewlett and ME Lamb (eds). New Brunswick: Transaction Publishers.

Li R, Fein SB, Grummer-Strawn LM. 2010. Do infants fed from bottles lack self-regulation of milk intake compared with directly breastfed infants? Pediatrics. 125(6):e1386-93

Prentice AM and Prentice A. 1988. Energy costs of lactation. Annual review of nutrition 8: 63-79.

Prentice A, Prentice AM and Whitehead RG. 1981. Breast-milk concentrations of rural African women I. Short-term variations within individuals. British Journal of Nutrition 45: 483-494.

Saxon TF, Gollapalli A, Mitchell MW, and Stanko S. 2002. Demand feeding or schedule feeding: infant growth from birth to 6 months. Journal of reproductive and infant psychology 20(2): 89-99.

Severn Nelson EA, Schiefenhoevel W, and Haimerl F. 2000. Child care practices in nonindustrial societies. Pediatrics 105: 75-79.

Shah PS, Aliwalas L, and Shah V. 2007. Breastfeeding or breast milk to alleviate procedural pain in neonates: a systematic review. Breastfeeding medicine 2:74-82.

Tilden, C.D. & Oftedal, O.T. (1997)Milk composition reflects pattern of maternal care in prosimian primates. American Journal of Primatology 41: 195-211.

Woolridge MW. 1995. Baby-controlled breastfeeding: Biocultural implications. In: Breastfeeding: Biocultural perspectives. P. Stuart-Macadam and KA Dettwyler (eds). New York: Aldine deGruyter.

Woolridge MW and Baum JD. 1992. Infant appetite-control and the regulation of breast milk supply. Children’s hospital quarterly 3:133-119.

Woolridge MW and Fisher C. 1988. Colic, 'Overfeeding,' and Symptoms of Lactose Malabsorption in the Breast-Fed Baby: A Possible Artifact of Feed Management. Lancet 13: 382-384.

For more references pertaining to the infant feeding schedule, see my article on breastfeeding on demand.

Content of "The infant feeding schedule" last updated 3/14