How do babies learn to like different foods?
Last time we talked about how babies are born with specific preferences (for sweet and salty flavors) and aversions (to bitter flavors). While these preferences probably never change entirely - does anyone really prefer the taste of kale to the taste of a chocolate chip cookie? - they can be modified, most easily through early experiences with foods and flavors. This process seems to be a little bit different for young babies and older children, as you would expect. For now, we are going to focus on how babies learn to accept the taste of unfamiliar and bitter foods such as vegetables, which we know they will instinctively reject when they first encounter them.
Before we get into this, I want to note that while I am focusing on the process of learning to like certain foods such as vegetables, I do not believe that children should or will ever only eat so-called “healthy” foods, or that this should be a parent’s goal. Any food that is important or desirable to your family should be regularly offered to your children - food and eating serve much larger purposes in our lives than simply providing nutrition, and it is important to avoid restricting or vilifying specific foods or categories of foods. However, most kids do not need exposure to cookies, pizza or ice cream in order to appreciate them. I can spend an hour preparing my kids’ favorite dinner, and the highlight will still be their bubble gum-flavored allergy medicine. Children naturally accept and prefer sweet and/or palatable foods, and if the goal is a more varied diet and comfort with diverse tastes and textures, some flavors and foods will require more effort than others. Let’s discuss.
How do babies learn about taste?
First we need to acknowledge that there are many different factors that determine what people eat. Access to resources is a major one, both the ability to purchase certain types of food and the time required to prepare it. But setting aside issues of access, babies and kids and, to a large extent adults, eat what they like. We all decide what we like based on how it tastes, as well as other sensory properties such as texture. Quick terminology lesson: the terms flavor and taste are often used interchangeably, but flavor is actually the combination of different sensory properties of a food or beverage, including taste, texture, and aroma.
There are three prime opportunities in early life to expose babies to different tastes and eventually flavors. The first is before they are born, when they are exposed to flavors from their mother’s diet through amniotic fluid. Biochemically speaking, babies’ diets consist primarily of glucose, a basic sugar molecule. However, the sense of taste is well-developed by the third trimester of gestation, and babies in fact experience a vast buffet of different flavors as they are floating around in the womb... if the mother is eating a variety of flavors. Of course, the reality is that even the most well-intentioned mother may be unable to consume vegetables, meat, certain spices, or other foods or flavors during her pregnancy for various reasons including food access, aversions and/or nausea. But if it possible to work in some variety then the baby will taste it! Research has shown that babies are more accepting of certain flavors if the mother consumed foods containing these flavors during her pregnancy. This research is super interesting especially because of the flavors that were studied, including garlic, anise, and carrot!
The next opportunity comes with breast- and/or formula-feeding. Flavors (really still just taste and aroma at this point) from a breastfeeding mother's diet pass readily into her breast milk, and if a baby is breastfeeding, she is again exposed to flavors of the foods that her mom is consuming. This can provide another opportunity to expose the baby to a variety of flavors, and babies who are partially or fully breastfed tend to be more accepting of new foods later on, probably because their flavors are familiar. Breast milk also has a sweet taste. Of course, not all mothers can or choose to breastfeed for a variety of reasons, and it can be helpful to understand that formula-fed babies might not accept new foods as readily as breastfed babies because they are not as familiar with the different flavors at that point. Formula does have a distinct flavor, but it doesn’t vary between feedings and babies seem to retain a preference for the specific flavor of the formula that they are used to. One very cool study found that 5-year-olds who had been fed as infants with soy or hydrolysate formulas, which have a strong sour/bitter taste, preferred bitter- and sour-flavored juice and were more likely to prefer broccoli as compared to children who were fed with sweeter-tasting milk-based formulas in infancy.
The third opportunity comes when parents actually start introducing their child to food. Even if mom ate nothing but pancakes during pregnancy and the young baby was nourished with a single type of infant formula, this period (scientifically termed “complementary feeding”) is an amazing time to help babies learn about new flavors. Complementary feeding is also exciting because many people can help to feed the baby. And this is the first opportunity to broaden flavor experience by introducing different textures. Some research has even suggested that babies’ flavor preferences can be “reprogrammed” during complementary feeding, regardless of what they were exposed to during earlier periods of their life.
Once babies start to experience actual foods and gradually transition to eating and drinking (mostly) the same things as other members of their families, caregivers can help them learn that there are many safe, available sources of energy and nutrition other than those that taste sweet. This can be thought of as reconditioning a baby’s instinct to readily consume any sweet-tasting item that is available to ensure that he is able to take in enough energy to survive. With young babies there are really just two basic principles to follow here, which we will call variety and repeat exposure. Before we discuss these in more detail, I also want to emphasize that positive experiences with food are always most important – babies and children should never be forced or coerced into tasting or eating anything they don’t want, and exposures to new and less-preferred foods should be relaxed, low-pressure and comfortable.
1. Variety: Introduce your baby to lots of different foods
This is probably one of the most important things that parents can do early on to help their child get comfortable with different tastes and textures. Some research has shown that introduction to a variety of vegetables during complementary feeding increased acceptance of new foods up to two months later, and that this association might be even stronger among babies who are breastfed. There also seems to be some extension of familiarity with one food to acceptance of other, similar foods - so exposure to a variety of fruits increases acceptance of other fruits, but not vegetables.
It can be expensive and exhausting to make a new item for your child at every meal, and this can also start to seem like a ridiculous waste of food, time and energy when baby is just smearing the food into her hair. Variety exposure doesn’t need to require a lot of time and effort, nor does it require an expensive subscription that will provide various baby foods on an allegedly optimal schedule for introduction. Babies can simply be given a taste (in age-appropriate form) of whatever the rest of the family is eating, and jarred or prepared baby food purees can be split into multiple portions and frozen in ice cube trays.
An important point to note here is that if you are interested in exposing your baby to more bitter vegetable flavors, check the labels of commercially prepared baby foods and make sure that the flavor that you want your baby to try (e.g. broccoli) is not mixed with something that tastes sweeter, like a fruit or sweet-tasting vegetable. This is common in the multiple-ingredient baby foods or “blends” (typically labeled as Stage 2 or beyond), and research has indicated that babies will not perceive the vegetable flavor when it is consumed with a sweeter flavor, which means that they will not start learning to accept that flavor. This definitely doesn’t mean that your baby shouldn’t also be exposed to foods with sweeter flavor profiles like fruits, sweet potatoes, and squash, just that these foods should be offered separately from green vegetables if the goal is to familiarize the child with the tastes of more bitter vegetables.
Also, while guidelines now recommend that most babies be introduced to potentially allergenic foods (e.g. peanuts, eggs, cow’s milk, fish) along with other complementary foods at around six months, pediatricians will sometimes recommend spacing the first introduction of these or other new foods in case of a reaction, so that the food that caused the reaction can be easily identified.
2. Repeat exposure: continue to offer new foods, especially those that your baby refuses the first few times
Again, let’s be clear that babies will not like many vegetables the first (and probably the 5th, 8th, and 10th) time that they try them. Most babies will make this very clear by making disgusted faces, pushing their disliked foods onto the floor, spitting them out, and any other dramatic reactions that they can come up with to make their preferences known. Some babies will have a similar reaction to foods such as meat or fish, particularly if these foods are presented with some texture - that is, not in the form of a smooth puree. These reactions do not indicate that your baby is a person who does not like green beans/chicken/squash. They simply indicate that he is a baby who is displaying the natural reaction that babies have to foods that do not taste sweet or familiar. Babies are designed to reject tastes that might mean that something is going to poison them if they eat it until they learn through experience that the food is safe. But this is fine, because parents and other caregivers can help babies learn that vegetables, meat, grains, cheese, etc. are a normal and safe part of the diet in the world that they are living in. Research has suggested that babies will start to accept new foods after they have tasted them 8-12 times on average. As mentioned above, babies who were breastfed seem to be more accepting of new tastes, likely because they have experienced them before if their mother ate something with that taste while breastfeeding, and babies who were fed formula might require a few more tastes before they will accept new foods that taste different than the formula that they are used to. While most of the research on repeated exposure has focused on fruits and vegetables, there is some evidence suggesting that this strategy is effective for other types of foods and there is no reason to think that it wouldn’t be.
Finally, repeat exposure does not apply to foods that the child seems to be having an adverse reaction to - this situation should always be discussed with a healthcare professional to see if continued offering of the food is recommended.
A few final points before we wrap up:
Even babies who are accepting a wide variety of foods during infancy will likely start to prefer some version of the “beige diet” around age 2 – this is the beginning of the neophobic or “fear of new things” period, though with food this tends to extend to a rejection of even many familiar things. This is a normal part of development and many children will start becoming more accepting of new experiences, including foods, again at around age 5.
Parents with an older child who prefers a more limited diet can still offer more variety in a low-pressure way – kids can get more comfortable with foods that they have refused in the past with positive, low-pressure exposure. The key here is to make the food available but not to hide it, force the child to try or eat it, or use other pressuring tactics like bribery or rewards. We’ll talk more about how older kids can become more comfortable with different foods next time.
The points discussed here are all generalizations based on research intended to characterize the typical process of developing food preferences. Some children will prefer a much more limited diet even with broad exposure and some kids are naturally more adventurous than others even with more limited exposures. There are also certain medical issues that can impact how children experience and respond to food, which can be discussed with an appropriately trained professional. Again, parents should never pressure or force children to eat anything – this includes bribing, coercion, etc. as this has been shown not to work (we’ll discuss this in depth more another time) and can have harmful effects.
References
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Mennella, J.A. and Beauchamp, G.K. (2002). Flavor experiences during formula feeding are related to preferences during childhood. Early Hum. Dev., 68, 71–82.
Spahn JM, Callahan EH, Spill MK, Wong YP, Benjamin-Neelon SE, Birch L, Black MM, Cook JT, Faith MS, Mennella JA, Casavale KO. Influence of maternal diet on flavor transfer to amniotic fluid and breast milk and children's responses: a systematic review. Am J Clin Nutr. 2019 Mar 1;109(Suppl_7):1003S-1026S. doi: 10.1093/ajcn/nqy240. PMID: 30982867
Disclaimer: The content provided here is accurate to the best of my knowledge and is intended to be used for informational purposes. It should not be considered a substitute for professional medical advice or treatment.