I’ve heard several times now about this idea that babies are in ketosis, and in other words are “keto-adapted.” This idea is then used to support the ketogenic diet in human adults. Let’s break this idea down here and examine its veracity.
Babies? Huh? What Age Group?
It’s important to define our terms. I’ve heard the saying “babies are in ketosis” rather than “infants are in ketosis” or “infants less than 6 months old are in ketosis.” What age group are we talking about?
Infants are rapidly growing little people. Thus it become problematic already to assume that just because we have been in ketosis for a period of time during our breastfeeding careers we may be able to continue it as our bodies grow in every way and direction. So we’re really talking about infants, and more specifically, the typical age that breastfeeding occurs. Since this is pretty variable I can’t specify an exact age, but I’m guessing 12 months or less.
It would also be interesting to discuss how the energy needs of infants may change as they develop physically. I would expect that as they learn to crawl, walk, and run, their bodies might start to prefer glucose.
Adults who go on ketogenic diets typically go through an adaptation phase for the first two weeks of the diet. This adaptation period usually brings some discomfort, GI symptoms like constipation, and fatigue (which is often corrected with additional electrolytes). After this period, many people feel better and it is believed they have “adapted” to ketosis.
Infants however are in a state of mild-ketosis. Their brains use ketones more so than the adult brain. From this paper (which has a very strong point of view and suggests that brains “prefer” ketones, which is up for debate):
“Postnatally, the brain’s dependence on ketones is made possible because infants are normally in a sustained state of mild ketosis (0.2–0.5 mM β-HBA). This neonatal ketosis is present regardless of whether the infant has just been fed or is in a post-prandial state, i.e., the ketosis is not a function of food restriction or hypoglycemia”
But infants brains are also not developed yet, and so this finding doesn’t make me want to jump on the ketosis bandwagon. What if their energy needs start to change? What would development be like if children were forced to stay on a ketogenic diet?
From the above quote, I gather that regardless of diet, infants preferentially metabolize ketones. This isn’t a function of their diet, but the developmental period they’re in. If our bodies then stayed in ketosis as we gained muscle mass and all our organs grew, it would make sense to be on a ketogenic diet. But that’s not what happens. This much is quite obvious to me based on intuition but let me share a quote from this article:
The increases in cerebral glucose utilization with advancing age occurs as a consequence of increasing functional activity and cerebral energy demands. The levels of expression of the 2 primary facilitative glucose transporter proteins in brain, GLUT1 (blood-brain barrier and glia) and GLUT3 (neuronal), display a similar maturational pattern.
So if that sounded like jargon, what they’re saying is that as babies mature and grow, they have more glucose transporters (the GLUT receptors) which enables glucose transport in and out of cells. After we exercise, expression of GLUT 4 increases in skeletal muscle too.
What this implies is that with maturation, our preference for glucose increases. Now what is unknown is what would this increased expression of GLUT receptors look like if children stayed on a ketogenic diet after the breastfeeding period ended? Now that would be interesting, and I feel myself traveling to new rabbit holes again, so I’ll have to look into that another time.
Infants reach many milestones as they grow. How do you think this would affect an infants energy requirements? I will summarize some findings from this article.
2 months: holds head up with support
4 months: holds head up without support, plays with toys
6 months: can roll over, sits with support
9 months: crawls, sits without support, stands with support
12 months: stands without support, moves into sitting position without support
18 months: can walk and run
As you can see, it takes several months for an infant to learn to walk. As it learns to walk, it’s also gaining weight, building muscles brains, organs, and everything else. When it started out, it was just a cute lump of fat that couldn’t walk.
It makes more sense for a lump of fat therefore to benefit from ketosis.
Assuming that the ketogenic diet helps a babies’ brain grow, and therefore adults can benefit from it too, is foolish for a few reasons. First, a babies’ brain is growing not just because of the diet. Experience is very very important too–just as important as diet. Touch, sounds, language, AND the nutritional input are all required for a healthy infant’s brain to grow. And of course, much of this growth is regulated by epigenetic and genetic influences.
It’s very common to assume that diets are the cause of everything in the world of nutrition. (Diet played a central role in my life several years ago and I believed that all my problems could be fixed with a change in diet). Here’s a quote I found from a ketogenic-diet-obsessed blog article talking about this:
The period in which human brains grow the most, and in which food is least likely to be different from evolutionary conditions, is a ketogenic period. This suggests that a ketogenic metabolism is excellent for learning and development.
No, it doesn’t really. There are a myriad of other factors influencing brain development and this is not a reason to go into ketosis.
Vegans Make up Myths like this Too
A vegan myth that is exactly analogous to this one is that the strongest animals on earth are herbivores, and therefore, humans should be too.
Conclusion and Summary
This myth is incorrect for several reasons, but the main reason is that we are not infants, and have a developed nervous and musculoskeletal system with far greater energy requirements than the infant who cannot even crawl yet. Suggesting that a ketogenic diet is something we are suited for just because the infant spends some time in mild ketosis is a bad comparison.
Secondly, the infant in a mild state of ketosis still benefits from glucose, which also helps the infant grow, by increasing the secretion of insulin-like growth factor 1 (IGF-1) among other mechanisms. Unfortunately, it doesn’t seem like this can be mimicked by adults; even small amounts of carbohydrates can drive the adult on the ketogenic diet out of ketosis. Thus, the rage in that community is carb-cycling. This is still ridiculous to me.
The last reason why this myth is dangerous is that it promotes black-and-white thinking. Our brains can use ketones and glucose for fuel. Why are we only focusing on the health benefits of ketones and ignoring the role of glucose in our bodies? People have become afraid of glucose as well as fructose, failing to see the middle ground. In the near future I will explain the health benefits of glucose in our bodies as they are immense.
I currently cannot recommend the ketogenic diet because its proponents seem to get carried away with beliefs like the idea that babies are “keto-adapted.” It is true they are in mild ketosis, but it is also true that you are not an infant and thus may not benefit from being in ketosis as much as an infant does.