Visit your local vitamin shop, and you’ll find dozens of “keto” powders, potions, and pills. I think it’s safe to say the ketogenic diet has not just “arrived,” it has set up camp on our couch, commandeered our remote control, used up all our wi-fi bandwidth, and has designs on starting an alt-rock band in our garage.
But amid all the fad-friendly protein powders and shakes (none of which, by the way, are necessary for achieving or maintaining a state of fat-burning) one thing you won’t find is the oldest and most ketogenic meal-replacement shake of all: human breast milk.
It’s true — up to half of the calories found in breast milk come from fats, much of it in the form of medium-chain triglycerides (MCTs). MCTs are a particular type of oil that is converted quickly and easily into ketones by the liver, and is often sold these days (in the form of refined coconut oil) as a supplement for keto dieters.
So believe it or not, babies spend much of their time in ketosis — an idea explored at length by Stephen Cunnane, PhD, a professor at Sherbrooke University and author of Survival of the Fattest: The Key to Human Brain Evolution.
the aging brain
I heard Dr. Cunnane speak at this year’s Metabolic Health Summit, where he presented a recent trial in which patients with early-stage Alzheimer’s, in the form of mild cognitive impairment (MCI), were given an MCT supplement for six months. When compared to a placebo, the supplement “had a clinically meaningful effect on some cognitive outcomes directly related to risk of progression toward Alzheimer’s disease, and significantly improved brain energy supply.”
This trial gives more evidence for the growing idea that Alzheimer’s is a brain energy problem, and points toward future treatment possibilities — pretty exciting in a field that has seen very little progress over the years.
I was reminded of that talk when Dr. Cunnane appeared on Vinnie Tortorich’s Fitness Confidential podcast last week. The interview was wide-ranging and covered a number of fascinating topics, including how to care for your brain as you age, but also the role of ketones in brain development among the youngest among us.
baby phat
One of the really interesting points that Dr. Cunnane makes: humans are the only mammals that are born obese. “I should have called the book ‘Survival of the Fattest Babies,’” Cunnane says, “because that’s really the point I was trying to make.”
In the interview, Vinnie points out that horses are born lean, and young foals are able to walk pretty much right away. Humans, on the other hand, come out chonky as can be, and are totally dependent on their parents. Why would evolution hand us such a disadvantage? The key, Cunnane says, is between our ears.
The brain is an energy hog. In adults, the brain uses up 20% of our total energy, despite only representing 2% of our weight. In newborns, the rapidly-growing brain gobbles up an estimated 50% of a child’s calories. Where does all this energy come from?
Lots of it comes from mother’s milk, of course, but some comes from those pinchably cute thunder-thighs that babies are known for. In an article in the Journal of Human Evolution, Cunnane and his colleagues say that fetuses begin to accumulate body fat during the third trimester of pregnancy, and “By providing fatty acids for ketone production that are needed as brain fuel, this fat layer supports the brain’s high energy needs well into childhood.”
food swamps
Another interesting point from that same article: Given the range of nutrients that the brain requires — including iodine, iron, zinc, and omega-3 fatty acids, among others — and given the places where these nutrients can be found in nature, it’s very likely that we evolved as a coastal species, living on “A shore-based diet, i.e., fish, mollusks, crustaceans, frogs, bird’s eggs and aquatic plants,” which “provides the richest known dietary sources of brain selective nutrients.”
So important are these nutrients, Cunnane says in the interview, that “to tell pregnant women not to eat fish [due to concerns about mercury] is basically criminal.” He believes that the risk of getting too little of these nutrients far outweighs the risk of getting too much mercury.
I’m always interested in the idea of an ancestral diet, and while I’m not about run out and stock up on escargot and frog’s legs (yuck!), I do find it fascinating that Dr. Cunnane’s research connects such far-reaching areas, from birth to old age, from the prehistoric to the cutting-edge. It makes me wonder: perhaps the future of medicine, and the answers to some of our most difficult problems, can be found deep in our past… and vice-versa.