007: Help! My toddler won’t eat vegetables

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Transcript Hello and welcome to episode 7 of the Your Parenting Mojo podcast, which is called Help!  My toddler won’t eat vegetables!  I decided on the theme for this episode when I was sitting in a restaurant with half an eye on a toddler and his parents at the next table.  The parents were trying to get the toddler to eat some of his broccoli before he ate the second helping of chicken that he was asking for.  All of a sudden a line from Pink Floyd’s album “The Wall” popped into my head: “If you don’t eat yer meat, you can’t have any pudding.  How can you have any pudding if you don’t eat yer meat?”  This is the way I was raised; you finish everything on your plate and you certainly don’t get dessert if you don’t finish your meal.  But as is the custom with the Your Parenting Mojo podcast, I want to use this episode to question why we do this and find out what scientific research has to say about it all.  We want our toddlers to eat a balanced diet, and we assume we have to teach them what a balanced diet means.  But do we really?  Or can we trust that our children will eat the foods that they need to be healthy?  These are some of the questions we’ll set out to answer today. Perhaps you might be as surprised as I was to find that the single study that grounds virtually all current research on children and eating was published in 1939 by a pediatrician named Clara Mae Davis.  She convinced unmarried and widowed mothers who couldn’t support their families to place their children into an orphanage in Chicago.  Davis then recorded every single thing 15 children ate over the first 4 ½ years of their lives after they were weaned.  In addition she recorded their height, weight, bowel movements, bone radiographs and blood tests at various intervals during those years. But the really interesting part of the study is what she offered the children to eat and how she offered it.  She created a menu of 34 different foods, all procured fresh and minimally prepared.  Some of the foods were milk, apples, turnips, lettuce, oatmeal, barley, beef, bone marrow, brains, and haddock.  The 34 foods were selected because collectively they offered the complete set of nutrients needed by a growing person although of course they weren’t all served at once – about 10 were prepared and served at once to offer a wide variety of foods at each meal. The nurses feeding the children were not allowed to directly offer or even suggest that the children try a particular food.  Only after the child reached for or pointed to a dish could the nurse put some food on a spoon and, if the child opened his mouth, put it in.  The nurse wasn’t allowed to comment on what the child ate or didn’t eat, attract his attention to food or refuse him any food.  The child could eat with his fingers if he wanted and no correction of his manners was offered.  The tray of food was taken away when the child had definitively stopped eating, usually after 20-25 minutes. As Clara Mae Davis noted, the remarkable thing about the results in this study is that nothing remarkable happened.  All of the children had hearty appetites.  Constipation was never an issue and other than mild colds, they rarely got sick. Five children were malnourished at the beginning of the study and all were healthy by the end.  The children ate, on average, roughly the caloric intake recommended by both the nutritional standards in place at the time as well as the standards we use today.  Current  dietary guidelines published in 2010 state that children aged 1-3 should get 5-20% of their calories from protein, 45-65% from carbohydrates, and 30-40% from fat; the percentages shift slightly in favor of protein and away from fat for children 4-18 years old.  In Davis’ 1939 study the average distribution of calories per kilogram of body weight was 17% protein, 35% fat, and 48% carbohydrates.  Individual children might have had protein intakes as low as 9% or as high as 20% – all still within the dietary guidelines.  So the children in Davis’ study met dietary guidelines developed sixty years afterwards, with all of the knowledge we have now and didn’t have then about how the body works, and they did this by themselves with no information or encouragement at all from anyone else, which I think is absolutely remarkable. I should also say that, as you may have observed with your own children, the children in the study were consistently inconsistent with the types and amounts of foods that they ate.  One child had a pint of orange juice and liver for breakfast; another had several eggs, bananas, and milk for dessert.  No single meal was what we would think of as “balanced” when we put a plate of meat, potatoes, and vegetables down in front of our child – but the children’s diets were on average extremely well-balanced. Now the kicker in all of this for us, of course, is that the children didn’t have unlimited availability of all kinds of food.  Vegetarians and vegans might argue with me about the health properties of animal products but the foods presented to the children in the study were selected because together they provided the complete set of nutrients the children needed.  Cereals were whole grains; no sugar or salt was added, butter, cream, and cheese weren’t used, and no canned foods were allowed.  Does that sound like the kind of food you eat at your house?  We do pretty well on the whole grains, but we certainly use all of the other foods that Davis banned from her study.  So if we accept that children can eat a healthy diet if they are presented with only healthy food, our task now is to try to understand how to apply this knowledge in the real world of our everyday lives today. I did a literature review for a paper for the Masters degree in Psychology that I’m working on and I couldn’t find any study that definitively shows what kind of behavior or actions parents can use that will have the outcome of children eating balanced diets in the short- and long-terms, largely because longitudinal studies are really rare (because they’re expensive and you don’t get to publish the results for a long time) and they generally don’t establish causation either.  But I did find a slew of other studies that can help us to understand how to support the development of healthy eating habit in our children. Leann Birch at the University of Georgia seems to be a luminary scholar in this field; if you check out the references for this episode you’ll find that around half of them have her name attached to them – and I wasn’t specifically searching for her work.  She and Jennifer Fisher at Temple University conducted a review of studies related to the development of eating behaviors in children that I’ll delve into in detail, pulling in the results from other studies as well.  Birch and Fisher start by noting the prevalence of obesity in children, some – but not all – of which can be explained by genetics; some of the rest of the explanation could be related to similarities in diet of parents and children: so if parents eat a lot of high-fat food then children are likely to have high-fat food available to them as well..  They note that very little research has been conducted that looks both at energy intake and expenditure, and it takes both sides of that equation to really understand obesity.  Children in the U.S. tend to eat too much fat and not enough complex carbohydrates, which is why public health messages now focus on increasing the amount of fruit, vegetables, and whole grains instead of just eating less fat. But other studies have found that the only significant predictor of increased fruit and vegetable consumption is a preference for fruits and vegetables – in other words, children who like fruits and vegetables eat fruits and vegetables.  So what causes children to like fruits and vegetables?  There’s evidence from several studies that these preferences are formed very early on in children (and also rats) who are breastfed, as children are exposed to the flavors of their mother’s diet through the milk, and as a result breastfed infants initially show greater acceptance of new foods than formula-fed infants. Once children start to wean they are predisposed to prefer sweet and salty tastes, and reject sour and bitter tastes.  They quickly learn to associate flavors with how they feel after eating (and they prefer foods that leave them feeling full).  I’m sure most parents realize that children are predisposed to reject new foods but one study found that 5-10 repeated opportunities to consume new foods can lead to increased acceptance.  So if your child says she doesn’t like a food the first time you offer it to her, keep trying.  Keep trying 5-10 times, and maybe one day she’ll just eat it. Another big topic is modeling of eating behavior.  Since eating tends to be a social occasion for children, the social context of meals becomes a model for the child.  One study showed that when preschoolers watched other children choosing and eating vegetables that the observing child didn’t like, the observing child began to like the vegetable more and ate more of it.  Another found that toddlers put foods in their mouths more readily when their mothers put the same food in their mouths compared to when a stranger did, which may not come as a surprise to any parent whose child wants whatever they’re eating.  When my toddler sees me come out of the kitchen with a bowl in my hands she immediately says “Want some.  What is it?” – because she wants whatever I have before she even knows what it is.  Children also look to their parents to understand what is the right amount to eat.  Studies have shown that dieting daughters are more likely to have dieting mothers, and parents who eat a lot are more likely to have children who eat a lot. I want to delve fairly deeply into the idea of parental control because I think it’s a strategy that a lot of parents try to use without knowing just how completely it can backfire.  Leann Birch has been active in this research as well and in general has found that the more we try to control children’s eating, the less control we seem to have over it.  For example, child-feeding strategies that encourage children to consume a particular food increase children’s dislike for that food, so by encouraging your child to eat more broccoli you decrease their liking for it, and we already saw that the only factor that predicts whether a child eats broccoli is whether she likes broccoli.  A survey of parents found that 40% spontaneously reported that restricting or forbidding the consumption of a certain food would decrease their child’s preference for that food, but research shows the exact opposite: when parents withhold a “bad” food children’s preference for that food increases and intake of the “bad” food can sometimes increase as well.   Esther Jansen and her colleagues at Maastrict University in The Netherlands managed to move beyond the correlations that these types of studies usually offer to demonstrating a causal link between parental control over children’s eating and children’s consumption of snack foods by testing whether prohibiting children from eating snack foods would lead to an increased desire for that food, followed by over-consumption once the restriction was removed.  The researchers provided children with two bowls of M&Ms (one containing yellow and the other red M&Ms), and two bowls of salty chips (one yellow; the other red).  Some children were instructed not to eat the red foods, were then asked how much they wanted to eat the red foods an how full they felt, and in a later test they were allowed to eat as much as they liked from any bowl.  These results were compared with those from children who were allowed to eat freely throughout the experiment.  The children who weren’t allowed to eat the red food consumed more of the red food in proportion to yellow foods, although they didn’t actually consume more food altogether.  And we should note that the authors of this study should be commended for demonstrating causation rather than just correlation, it isn’t clear to what extent the findings of this highly controlled lab study are applicable in a home setting where a wider variety of foods that may be equally unpalatable (like broccoli AND green beans) might the things children get to choose between. And what about the issue of the amount children eat?  It turns out that even infants are capable of regulating their caloric intake.  One set of researchers added more or less formula to the bottles of six week-old infants, and found that the infants drank more of the formula that was more watery so their overall caloric intake was the same as the infants who drank less of a stronger solution.  But parents who bottle feed might inadvertently pressure their child to override the child’s hunger cues by getting the child to finish the last bit of liquid in the bottle – I remember doing this with my daughter as well when she drank pumped milk from a bottle.  You don’t want to waste something that’s such a hassle to get in the first place!  Leann Birch did another study that essentially replicated this with children who were eating solid food – they adjusted the fat and carbohydrate content of the first course of a meal to make it more or less energy dense, and then tested how many calories were eaten in a second course and in subsequent meals.  She, too, found that children were able to self-regulate their caloric intake both within the same meal and also across the remainder of the 24-hour period.  But when researchers asked parents to reward children for cleaning their plates, the children stopped responding to the different energy density of the foods and began eating more in response to the rewards.  Another set of researchers noticed that parental prompts to eat were correlated with both time spent eating and the level of obesity in children, and also that these prompts to eat almost always followed food refusals by the child.  So the child says she’s not hungry; the