This is part of an ongoing series on moderation. It’s in preparation for my next book and includes expert interviews, the latest research and expert tips. Sign up for my updates to get these posts and subscriber discounts including FREE e-book offers.
You serve dinner with all the food groups and your kids first reach for the pasta, bread, rice, tortillas or whatever carb source you have on the table. After a while, you remind them of the other food on their table or plate. Maybe you get so frustrated you simply instruct them to eat some protein or veggies.
Believe it or not, a child’s preference for carbs is a key barrier to teaching them moderation. Not because they like carbs but because parents don’t always understand the why behind children’s preferences, and may end up drawing the wrong conclusions.
Lately, my research has revealed some interesting facts about kids’ eating I think every parent needs to know. So similar to this post on picky eating, let’s hear it from the kids perspective.
1. Carbs Signal Safe Energy
When we go places where there’s food, I know you want me to eat the protein and veggies — and all those mixed dishes — but the sweet and starchy foods just feel like a safer place to start. I think I can get around to the other items but these are safe bets and they satisfy.
What’s behind it:
The most common explanation for children preferring sweet over bitter is that it signals a safe source of energy. According to this review:
A sweet taste in nature indicates energy, which is needed for optimal growth and development. Therefore, it would seem safe for the young to consume foods with a sweet taste. Breast milk is also sweet, and this would confirm the link between a sweet taste and safe energy.
The preference for sweetness changes with age. In one study school age children (9-10 years), adolescents (14-16 years) and adults (20-25 years) were given a taste test with different sucrose concentrations. The school age children preferred the higher sweet concentrations than the adolescents but the adolescents preferred higher sweet intensities than the adults. This is consistent with other studies that show that sweet preferences decline when growth is complete.
2.It’s Brain Food
I know you look at me like I’m crazy when I’m perfectly content with eating bread at a meal or crackers at a snack sometimes. I don’t want to hear how I ate everything as a baby. My body and growth feels different now. I mean, eventually I want to more food combinations but sometimes this plain old starchy food just hits the spot.
What’s behind it:
Researchers from Northwester University set out to determine the energy costs of the brain from birth to adulthood. Using MRI and PET data, they discovered that glucose uptake by the brain doesn’t peak at birth as previously thought, but during the slow period of growth between infancy and puberty. During this time the metabolic needs shift from growth of the body to metabolic needs of the brain. For example, at birth 35.4-38.7% of daily energy requirements go to brain-glucose uptake but this climbs to 43.3-43.8 during childhood.
The researchers believe that this period of delayed growth in childhood evolved so the unique human brain can fully develop, not so much in size but in key processes like synaptic growth. In order to do this, the brain relies heavily on glucose, which is why a child’s brain uses twice as much glucose as an adults brain does. As the graph shows, brain glucose requirements peak at about five years of age, years before adult brain size is reached.
This may be why preschoolers and young school-age children are drawn to starchy carbs like bread and crackers that readily provide glucose to the developing brain. I showcase what this type of eating looks like when Big A was four.
3. Growth Made Me Do It
I know you want me to stick to one or two cookies, but that’s really hard for me to do. Remember, I’m new to eating and I have strong drive to eat them once I start. But I do get satisfied and am okay not eating them all the time. Just let me know when to expect them and we’re good.
What’s behind it:
In one study, children were given sweet drinks and then categorized into high sweet preference and low preference. These two groups did not differ in by age, body weight, stage of puberty, height or gender. Where they did differ is a measurement referred to NTx, a marker of bone growth that can be detected in urine. The results showed that the children that were still growing showed a heightened preference for sweets compared to those who had stopped growing (around 15-16).
The lead researcher of the study, Nancy Coldwell, was interviewed on NPR:
Exactly how this all works is still somewhat of a mystery, but Coldwell says that one important clue lies in the discovery that growing bones actually secrete hormones that can influence metabolism. Other well-known metabolic hormones like leptin and insulin have been shown to act on brain areas that control cravings and appetites, and even directly bind to the tongue, where they affect the preference for sweet tastes. Coldwell suspects that hormones from growing bones may be doing the same thing. In other words, it’s not your kid’s fault he raided the cookie jar – the hormones from his growing bones made him do it.
“I don’t know for sure, but I am very suspicious that the bones are somehow telling either the brain or the tongue that there is energy needed for their growth and signaling for that preference to increase,” says Coldwell.
This may explain why kids on low-carbohydrate ketogenic diets for seizures don’t grow as well as children on regular diets.
How This Information Helps
Understanding carbohydrates play an important role in growth can be helpful, and even a relief, for some parents. Instead of assuming a child is addicted to carbs, we can understand their natural biological drive to eat them. In her study, Nancy Coldwell sums up what this means in terms of feeding:
This elegant link between taste preferences and biological need may leave modern children especially vulnerable to the long-term consequences of overeating and caries in the advent of an abundant sugar supply. However if we accept sugar liking as a natural concomitant to growth in childhood, then it brings into question the assumption that this propensity is invariably unhealthy and undesirable among this age group.
So once again, it’s that middle ground that is best. If we restrict too much, it can result in what researchers call eating in the absence of hunger. And when these cravings naturally decrease with age, those that were restricted may have forgotten how to listen to their body. But if we allow kids free reign with food choices, their diet will be imbalanced, often too high in sugar and refined carbs.
What can you do? Set the eating schedule and offer a good share of quality carbs like fruits, whole grains, dairy and beans while offering sweets in a reasonable manner. Vary the food from meal to meal, but don’t interfere with the choices children make from what you offer (see Satter DOR for more on this).
The real key is understanding that moderation looks different for kids than it does for adults. This knowledge helps you stay consistent and prevents you from falling into the feeding traps that produce the opposite of moderation: extremes in eating.
Do you have a carb-loving kid? Tell me all about it in the comments.
Want more research-based strategies to raise a good eater? Check out my book: How to Raise a Mindful Eater: 8 Powerful Principles for Transforming Your Child’s Relationship with Food.