Optimal Weaning from an Evolutionary Perspective
0:00
My talk is called Optimal Weaning from an Evolutionary Perspective and I'd like to break down that title a little bit.
'Optimal' implies best for something, and here that something is going to be brain development.
The word 'weaning' can also benefit from clarification, because we often use it to mean the end of breastfeeding, but I use the convention meaning the beginning of the end, with the introduction of first foods.
For 'evolutionary perspective', I just want to point out that what we know about our past can inform our understanding of physiology, but our physiology can also constrain the possibilities of the past.
Overview
0:36
I've concluded that weaning infants onto an animal based diet best meets their nutritional needs, and the rest of this talk will be about why.
Primarily I'll be talking about the unique properties that resulted from the evolution of our brains. I'll also give a bit of evidence from modern health studies and trials, and then finally I'll give a little bit of the how, based on my own experience in weaning one of my children onto animal based foods.
Human brains are unique
1:08
Human brains are unique in many ways, but one of the most striking things is their sheer size, especially relative to our bodies. In particular, when you take into account that we are primates, it's really quite extraordinary. Primates already have brains that are about three times as large as most other mammals, at least relative to their size , and then humans have again about two and a half to three times as large brains as other primates do. And we didn't always have that large a brain, that three times expansion occurred over the course of a few million years.
And a second related way that our brains are unique, is that our individual human brains do most of their growth after birth .
Altricial vs. Precocial
1:53
It's helpful to think about this in context of the distinction between altricial and precocial animals, which is based on their degree of development at birth. Altricial animals are underdeveloped. They tend to have a short gestation, compared to precocial animals, who have a long gestation. They're poorly developed, so they may be missing hair. They usually have underdeveloped sense organs, for example unopen eyes. They're usually born in litters, as opposed to singletons, and they have less adult-like proportions, whereas precocial animals are essentially adult-like in their proportions. They have underdeveloped limbs, which means that they can't do what precocial animals do, which is move like the adults that they're born from, and they tend to be smaller at birth, and their parents are younger when they reproduce.
Humans appear altricial but are precocial
2:41
Humans don't really fit into this paradigm very well when you look at it at first glance, because they appear to be altricial, but they're actually better understood as being precocial. Primates in general are highly precocial, and humans, when they fit that, are to the extreme, for example, we have enormous newborns, and we reproduce relatively late. Our babies appear altricial, though, because they're born helpless, they don't have adult proportions at all, and they can't walk or have the motor skills that you would expect them to have.
But it's helpful to think of them as actually precocial, but born early. And one reason to think that is because of fetal brain growth rates. We have our brains growing at the same rate as fetuses do persisting for up to a year [ should say at least ] after birth, and if you then look at our babies when they are a year old they look a lot more like you would expect them to look if they were born precocial: they have motor skills that you would expect them to have, and teeth, for example.
Human bains continue to grow postnatally
3:52
Here's [sic] a couple of graphs from the Smithsonian. There's one for chimpanzee brain growth and one for human brain growth. As you can see with the chimpanzee brain growth, they complete about half of their brain growth in gestation, and the rest over the course of a couple of years. Note that chimpanzees, like many primates wean quite late compared to us ; they wean at about four years of age, which is well after all their brain growth is completed.
Humans, on the other hand, have a very steep rate of growth before birth, and it continues into the second year , , and then the rate slows down some, although it's still pretty significant, and then it's followed by what looks on this graph like a levelling off, but this graph does end at age 10 and we know that there are growth spurts after that, too.
Rapid brain growth sustained beyond weaning
4:40
What I want to draw attention to with that is that the fetal-like brain growth doesn't just extend beyond birth, but it also extends beyond the end of weaning. [This is a mistake. I meant to say that the rapid brain growth continues past the end of weaning, but it is "fetal-like" only past the beginning of weaning.]
So, we have this fetal-like growth in the first year, continued rapid growth to 5 years [ Or is it 4? ] , continued slower growth through childhood, and then, if you combine that with the fact that we wean early , we realise we need to support that kind of rate of growth even beyond weaning.
[ I'm also wondering whether weight is the best measure. Volume, density, cholesterol levels are all other measures to consider, but I won't get into that here and now. ]
Our brains are really vulnerable, and they have many critical periods, each of which builds on the one before, so if you haven't completed one of your stages of brain growth, you may not be able to complete the next stage successfully, and that means that you need continuous support through a long period of time .
Brain growth requirements
5:28
What kind of support do we need to give growing brains? Well there are at least three kinds of ways that we need to support a growing brain.
One is that they need specific micro-nutrients. Even adult brains can suffer if they don't get enough of certain kinds of micronutrients and certainly developing brains that are missing these nutrients, if they're missing them at critical times sometimes they can't even recover from the detriment.
Secondly brains require an enormous amount of energy. At least 20% of the energy that we consume as adults goes to our brain and that's even more extreme in a newborn who has about three quarters of the energy that they consume go[ing] right to the brain , .
And then thirdly, of course we need material for the structural components, and brains are made mostly of cholesterol and fat.
Brain evolution requirements
6:24
In parallel to that, the evolving of the brain has similar requirements. We needed those micronutrients and the energy and the structural components. We needed them to be available over a period of years for each individual and then that needed to be compounded more or less continuously for millions of years for us to be able to make that three times expansion.
Brain requirements: co-adaptations
6:51
While our brains were expanding over this long evolutionary period, there were co-adaptations that allowed them to expand, particularly contributing to the extraordinarily high energy requirements.
These co-adaptations I would like to talk about in more specifics: a high quality diet (by which I mean high in animal foods), shrinking intestines, a reliance on the ketogenic metabolism, and increased body fat particularly in babies.
Co-adaptation: eating meat
7:20
First of all, meat eating. The plants that were available to us at the time that we were expanding our brains were simply too fibrous, too low in protein, too seasonal, and too low in calories to provide the needed energy. So significant fatty meat eating was necessary for the protein and the energy as well as the micro-nutrients for developing our brains to our current form.
[ See the post, Meat is best for growing brains for more detail about the implausibility of plants as a sufficient food source.]
Brain requirements: micronutrients
7:39
I'm going to just zoom in on a few of those particularly critical micronutrients.
We have the minerals iodine , iron , and zinc ; the fatty acid DHA , which is in all your brain cells in the phospholipids. It's particularly important in vision (retinal cells) in the synapses, and vitamins A and D. If you don't get enough of these vitamins and minerals and fatty acids as your brain is developing you can suffer developmental delay, disability. There is a tendency to emotional fragility and susceptibility to psychiatric disorders and it's often not recoverable.
Micronutrient sources
8:27
For these micronutrients, animal foods are either the only, the best, or the most bioavailable source.
For DHA it's almost exclusively found in animals. It's true that there is some in microalgae, but it's not very plausible but that's where we were getting it while we were evolving.
Vitamin D is only available in animal sources. It's true you can get it from sunshine, but again if you take into account the seasonality and the various geological periods we went through, It's — we would need more.
Iron is available in plants, but it's three times more bio-available in animal sources . Similarly with vitamin A, which is 12 to 24 times more bioavailable in animal sources , . If you think about the sheer amount of plant food that you would have to eat to try to make up for that, it's just not plausible at all. For zinc it's simply — animal sources are simply the best.
And then I'd also like to note that some plants actually interfere with the absorption of those minerals, so it might not just be not a benefit to try to get them from plants but it could actually be a detriment.
[ I refer the interested reader to the blog of Dr. Georgia Ede, and in particular, her post on vegetables ]
Co-adaptation: shrinking intestines
9:40
A second co-aptation is shrinking intestines. In 1995 Aiello and Wheeler came up with a hypothesis to try to explain how it could be that these brains that we're growing which requires so much energy could have gotten that energy without giving up something else, and they noticed that we did give up something else. We gave up a drastic amount of the size of our intestines. Intestines are also really energy-intensive, so that smaller size freed up energy for the brain But there's also a feedback loop, because having less intestines reduced our ability to consume fibre. A lot of other primates get a lot of their energy by consuming fibre and putting them through the factory of bacteria that turns that fibre into fat. We no longer have much of that ability at all and so that also increased our need to get our fat directly from an animal based diet.
[ See the post, Meat is best for growing brains for more detail about the the Expensive Tissue Hypothesis, and shrinking intestines. ]
Brain requirements: structural components
10:30
Going back to brain requirements, I wanted to re-emphasize the structural components I'd said that brains are mostly fat and cholesterol. By dry weight it's about 60% lipids , about 40% of that which are cholesterol , but there's a problem because fatty acids don't cross the blood-brain barrier very easily , [ That is, DHA and AA enter the brain easily, but not the long chain fatty acids that white matter, gray matter, and myelin are mainly composed of. ] , cholesterol almost not at all . So all of that fat and cholesterol is reconstructed in the brain and it's reconstructed we know, out of ketone bodies [ See next two slides ].
Ketone body fates
[ This slide I inadvertently omitted! It shows the biochemical pathways of ketone bodies being made in the liver,and what is relevant for this talk, being transformed into fuel, as is familiar to many,but also into fat and cholesterol, which may be new to many in audience. ]
Co-adaptation: reliance on ketogenic metabolism
11:52
The fact that we use ketone bodies for brain energy and material, which we and some other species also do in gestation, explains why newborns are in mild ketosis all the time . Infants use ketones three to four times more efficiently than adults [ Correction! four to five times. (Three to four is in newborn rats.) ] , so mild ketonemia for a baby is more like a deeper ketosis for an adult. Even children as old as 12 and probably older can become ketogenic much more quickly and easily than you might expect. We're talking about a matter of hours of fasting to develop the kind of ketosis that would take adults several days . But even human adults become ketogenic more easily than other species and they do it without calorie restriction. This is really significant. I know of no other species that sustains ketosis without either starvation or semi-starvation, and it has implications for animal models of ketogenic diets therapies, because there may be cases where an animal requires caloric restriction for the therapy to be effective, whereas in humans it probably doesn't, and would be a detriment to compliance and to health outcomes.
So I wanted to emphasize that humans have co-opted this traitthat was previously an adaptation to cope with periods of starvation, and itstill is in other species, but we have co-opted it into a default metabolism atleast for the period of childhood to support the brain growth in particular,but also to meet the brain's ongoing energy requirements.
Co-adaptation: increased body fat
13:30
Finally, the last co-adaptation I want to talk about is increased body fat, because it goes along with all the others It's striking, again, when you compare humans with other primates, how fat they are. Even adults are fat compared to other primates. Other primates and most terrestrial animals actually have less than 5% body fat, and humans have easily somewhere between 15 and 20%, even very lean ones. Human babies take that to the extreme. They start out at about 15%. That's doubled in a couple of months and it continues to increase over the first year.
Baby fat is different in character from the kind of fat you'd see in obese adults. It's subcutaneous, not visceral , and it's very low in polyunsaturated fatty acids even if their mother is eating a lot of polyunsaturated fatty acids, whereas obese adults tend to have a kind of roughly corresponding level and quality of fatty acids to what they're eating. So there's obviously a lot of filtering going on. And what polyunsaturated fatty acids are there are almost all DHA and arachidonic acid, which is another important brain fat, so it seems that this extreme body fat in babies is there to provide a continuous supply of fat that can be used by the brain both for energy and for materials via the ketogenic metabolism that we are relying on .
Summary of Evolutionary Evidence for Meat
[ This is the other slide I missed.]
14:56
I seem to be missing a slide.
I just wanted to quickly summarize what what I've said about evolution of the brain. The first is that we needed to evolve — we needed to eat meat to allow us to evolve the brains that we did. That's for energy and for micronutrients. And I also wanted to emphasize the ketogenic metabolism part, because not only is it a natural normal default state for children but it shows that it's not detrimental, it's actually a benefit. It's actually critical. It's actually part of the mechanism of how we build our brains.
And so I'm bringing that up because someone who's thinking about weaning their baby onto animal-based foods might worry: Wouldn't this make them ketogenic and could that be a problem? And I just want to emphasize that not only is it not a problem, it's the way it's supposed to be and you could hardly stop if you wanted to because even when they sleep they're going to go into ketosis.
Weaning onto meat: clinical trials
16:07
OK, so onto clinical trials. I know of two clinical trials that compared eating — weaning an infant onto the fortified cereals that we mostly recommend now, versus weaning them onto exclusively meat. The first one compared or took some measurements comparing them and the meat weaned children had a higher zinc status, which we know is very important. They had adequate iron without the benefit of supplementation that the cereal arm had. They had increased head growth which in children is a good index of brain growth, and it's also correlated with higher intelligence and that's not even taking into account the size of your head at birth so it's not just the size of their head, it's the amount of growth that happened between birth and the later time that's correlated with the higher intelligence. And the second study just showed better general growth without increased adiposity That was what the researchers were worried about was that if you wean babies onto meat they would get fat in a way that would increase the risk for modern diseases and that of course didn't happen.
Slide with refs
17:30
And I just have those references there for your reference. This kind of study is what I think has led to certain agencies like the Canadian government and the La Leche League to include meat as a recommended first food.
How? It's easy.
17:41
Finally I'm going to talk a little bit about how to do that just based on my experience from doing that with my third child. I was very influenced by Baby-Led Weaning. The core understanding from them is that you don't — you can basically give a baby the same food that an adult eats. The risk of choking has been greatly exaggerated. You don't need to buy into this whole, you know, factory-made baby food stuff. You can give them what you eat for the most part. So what I have done, for example:
I was in the habit of making bone broths that had some meat in the broth and I started by giving him broth on a spoon and increasingly over time added some fragments of meat.
I also gave him bones to teethe on from my steaks and chops, and again I increasingly left meat and fat on it, which he enjoyed a lot.
I fed him a lot of egg yolks and beef and chicken liver, which have a nice soft, silky texture. They're extremely nutrient dense and to this day — this child is almost seven and liver is one of his favourite foods which pleases me to no end.
I'm really grateful to Aaron for being the first to bring up the word pre-masticate in this conference yesterday, so I didn't have to be, and I also know from being in the audience that several people besides me did prechew their food for their babies and it's certainly plausible — I would expect that a lot of people in the past did that and I did that.
I also often made plain unseasoned beef jerky which is really good for teething — sort of reminds me of a dog with rawhide he would gum down on it and pull and then he'd suck on it for a long time and it would basically just disintegrate. Also still one of his favorite foods.
(Photo slide)
19:35
And I'll just leave you with a couple of photos of that baby who is almost 7. On the left here we have him at six months with a lamb bone that he was teething on. At the bottom: when he was two I discovered that he had liberated a stick of butter from the fridge, because that's so delicious, and by two-and-a-half he was scrambling his own eggs.
This child basically had almost no plant matter in his diet for the first two years of his life and even now his diet is primarily animal-based.
Please give me your questions. Thank you.
Q&A
I've included the names of the questioners that I knew. If you are one I left out, introduce yourself!
Again, my clarifications or further comments in brackets.
Question 1 (Christopher Kelly)
C: I fully(?) subscribe to your ideas presented here and I have a very healthy two and a half year old daughter that's eaten much the same way. But I thinks there's an important point missing from your talk that is: the ketones come from medium chain triglycerides, that come from mom's milk from eating carbohydrates. So the carbohydrates are synthesised in the breast tissue that make MCTs. Those MCTs are put in the breast milk, and that's a really important ketogenic substrate, so I think that mom should be in ketosis, You see what I'm saying? The ketones should be synthesised by the baby.
A: I understand what you're saying, yes. So I just want to give a couple of counter-examples. I didn't eat any carbohydrate while I was making breast milk, and although there are medium chain triglycerides in the breast milk, that's certainly not the only reason that babies are in ketosis. Even the babies postweaning that i mentioned earlier get into ketosis very rapidly, because it's just the natural state. You can make it — that's why what I'm positing here, and I'm not — it's not my idea — but what I'm saying here is that the baby fat that is there is being turned into ketones just from the fat that's stored on the body, just the same way that I make them
C: Right
A: And I forgot to mention that, I talked about how fat babies are and how fat adults are compared to other primates, and I think it's quite significant. It would be unusual to see an animal that's that fat if you thought that we weren't naturally ketogenic animals.
C: Yeah and I've actually measured ketones, blood ketones, in my daughter when she was still an infant, breastfed only, and it was 1.6 mmol. But I can actually send you the studies that show that the the MCTs in milk, they go down and there's studies where they've looked at giving MCTS to mom and they don't go anywhere. Mom metabolizes them all. None of them appear in the breast milk, so I think like the carbohydrates for mom, It's not my opinion, I can send you the studies that show that that might be important.
A: I'd like to see that. I guess what I'm trying to say is that the ketones that are in the baby's blood don't only come for a medium chain triglycerides...
C: Right, right, I understand that. Okay, yeah. I work with a doctor, he's just finishing his PhD in neonatal neuroprotection so he's done quite a lot of research in this area so I'll send you some studies.
A: That's fantastic. I would love that.
C: Okay, thank you.
Question 2
22:53
Q: Hey, that was great talk. Thank you. Can you say something about the timeframe and you're, you know after three children and all of your research and interest in this, your thoughts on the timeframe for beginning the weaning process and then also how large that window of transition looks
A: Sure. There's a lot I don't know but I know that the recommendation currently is to start weaning at around four to six months and I think that the reason for that is because the amount of breast milk that children get, the caloric input just can't provide much more than what they need by the time they're that large and so I would say to start giving your baby food as soon as they start to express interest in it. Just, you know, let them be the ones who say "I'm ready to start eating. Give me that." And then how long it goes: Humans tend to wean a lot younger than other primates and I don't know to what degree that's enculturated and to what degree that's natural. With my experience, my first child, I, he stopped breastfeeding at about two years and then each one after that was earlier and earlier with the last one, he stopped at nine months. So, I'm sorry I don't know more about that.
Q: No, no, it's okay. I just kind of wanted to see what your thoughts are. I suppose there's some, aside from nutritional implications of how soon or early or late you you move away from breastfeeding I'm sure there's other implications as well but it's just it's hard to understand. I just have a newborn, so I was just interested.
A: Congratulations!
Q: Yeah. Thank you so much!
Question 3 (Georgia Ede)
24:49
G: Amber, thank you for an exceptionally good talk. I just had a curiosity question as a psychiatrist. You having raised three children on this unique diet, which I wish were more common, [ Clarification: Unfortunately only my third child was weaning onto meat, though our household was always generally a low carb one. ] can you comment at all about how your children fared emotionally and physically compared to their peers? As a mother I would be very curious to hear.
A: Well there's so much individuality I don't want to necessarily claim too much. I know that my youngest child does have a very even temperament, especially compared to one of his brothers, but then on the other hand his oldest brother has perhaps the most even temperament of all, so don't I don't know what to conclude about that. One interesting thing that has been commented on to me many, many times is that my youngest child was never — he never missed a single day of daycare throughout — when he started at two and, so the entire three-year period, many of his peers, all of his peers missed significant time to many illnesses and he missed not a single day, so I like to attribute that to his diet.
G: Thank you very much. It was fascinating.
A: Thank you.
Question 4 (Ben Sima)
26:02
B: Has it been difficult to maintain his diet of high-fat from a social perspective, for example, they go over to someone else's house and they have candy or something with other parents?
A: It is a challenge and the older they get the more of a challenge it is. My other children also at the time that I was weaning him, they were also transitioning to a more meat-based diet and yes it's — I mean for example there, the number of special occasions that you have when you're at school seem to be almost as numerous as the number of days Like, it's always somebody's birthday or some occasion and that's always being celebrated with some kind of gluteny, sugary snack and yeah, it's a struggle.
B: So do you find that he has a sweet tooth or does he kind of shun that
A: He loves sweet things when he gets his hands on them, but he doesn't seem to be obsessed with them.
Question 5
27:04
Q: I just wanted to offer the cross cultural perspective that the worldwide age of breastfeeding cessation is about four to five years. [ But see footnote 3 below, which argues that the natural age is about 2.5 and for important, persuasive reasons. ] It's only in the United States that it's young, around a year, but if you look cross-culturally it is actually four years in most cultures.
A: Thank you for that. So that's for the very end of breastfeeding?
Q: Yeah. So that's kind of our biological norm. It's more of a cultural thing here. The other thing that's interesting is around four to six months — infants get a big bolus of iron from the placenta especially if we allow for delayed cord clamping — and then around four to six months that initial iron starts to go down which is another reason why, like you're saying, meats are such a good first food, but that's why that four to six months seems to be a good time to start foods is because that — not that breast milk is lacking in iron and zinc, but that that's not where they're supposed to get it from. You get for placentally and then it starts to go down around four to six months which is why, traditionally the idea of "ok let's put iron in rice cereal" which we know — not a good idea but yeah that's another reason why that four to six-month window seems to be a good time for getting those iron and zinc rich foods in.
Question 6 (Nick Mailer)
28:20
Q6: Thanks for the talk, it was very good. Something that hasn't been discussed so much in this community is that weaning and continued breastfeeding is not merely about nutrition but it's also about keeping the bond between the mother and the child, and that's something that's often overlooked. I know that there are people who I know who have generally weaned but, you know, when the child is a bit ill or is feeling a little bit insecure the child will revert for a little while to getting a little bit of breast milk or maybe once at night just to say goodnight. It becomes part of a ritual and part of a bonding process rather than as an essential continuing of nutrition, which is why as long as you're comfortable with it there's no harm in weaning in that extent, finally later, and that sometimes people feel the pressure — okay it's four to six months I better stop by six months or something will happen — and people do feel that pressure which is why I think in the US and the UK people kind of feel that it's a race to the final cessation of weaning and it doesn't have to be as far as I've heard.
A: Right. Excellent point. Thank you.
Question 7
29:22
Hi. Thanks for the talk. So I have three children also. My youngest is 15 months. We thought a very similar, you know baby led weaning process, as your youngest. My question is, so my oldest is 11 too — quite a gap in between them, and you mentioned that vitamin D is one of the critical elements for brain development and prior to my son being born I had never seen like my pediatrician recommending vitamin D supplementation. So i guess my question is what are your thoughts on supplementing, like, drops as a newborn, and also what are some of the better animal sources other than I think fatty fish to get vitamin D from.
A: Yes, liver fatty fish... I'm surprised that you didn't, weren't recommended vitamin D drops because I remember that from even 15 years ago when my first son was born.
Q: Yeah I don't remember if it's possible. Five years between each of them. So, I think that's weird you know.
A: Right.
Q: Did you do those?
A: I did. I did do those with the first two children. Actually I did it with all of them, come to think of it. Yeah.
Q: Thanks.
A: I figured there's — the amount you would have to get to overdose is high enough that it wasn't going to hurt.
Q: Yeah. We did it too. I just wasn't sure. I hadn't heard it before him, and you mentioned it, so thanks. Alright.
A: Thank you.
Question 8
30:53
Q: Hi. I missed the first part your talk which I'm bummed about, but I have a four-year-old who regularly steals butter out of the fridge, and her first foods were I think egg yolk, and I don't think I did liver right away because I wasn't doing that much liver but now she loves liver too. It's like her favorite food.
A: Isn't it good!
Q: Yeah, I mean I don't particularly like it, but I eat it. But she like — she loves it.
I just wanted to add, too, maybe this will be covered in the next talk, about breastmilk and the microbiome, but one of the things that I found interesting about breastfeeding and the importance of it for the longer term is that it actually, the way that children remove milk from the breast actually helps to form the jaw and the palate, and so we see a lot today where women have to go back to work, you know six weeks, 12 weeks after giving birth and so they're pumping a lot and because we're getting bottles and that's really changing the way that our mouths are structured, I mean as are our nutrients in the womb and the palate formation.
I mean, anyone familiar with Weston Price's work knows that, right, but I just think it's an interesting piece, too, and I don't think that there's this — once kids start food they have to stop breast milk. In fact those things go together quite well for a long time because of the emotional factors and because of the palate formation and the muscle strength and the jaw formation.
A: Right.
Q: So, that I think is an interesting interesting piece, too, and yeah I've seen the same sort of statistics that hunter-gatherers usually breastfed three to four years, but they actually had a lower body fat, and so that would suppress ovulation for longer, which is why their children were spaced 4-5 years apart.
And there was no dairy. People weren't eating dairy, so only dairy that was available was breast milk and the way that that dairy produces certain vitamins...
A: Lactose in particular is broken down into glucose and galactose and galactose is used to build some the brain material as well.
Q: There's a question, so I have anoher question I'll ask you later.
Question 9 (Kevin Boyd)
32:52
Q: Okay that was interesting. Who are you? That's, it's interesting that you'd, she's — that's my whole talk this afternoon. Please come.
Nutrition is concerned with nutrients, but not mechanical aspects of food processing and what she brought up was what I was gonna talk about a little bit, but how did you learn about baby led weaning, because, that is, for people who might not know could you explain a little bit about what it is and how you learned about it and how you are executing it with your own children?
A: Well, I'm not sure where I first heard of it, but the thing that I said that was the core important idea from it is what I've taken mostly from it, and that's that babies don't necessarily need you too mush everything up you can, you can give them a chicken drumstick and they'll deal with it.
Q: Yeah. I'm going to really elaborate and so many wonderful points you made today, at one-thirty today.
A: Ok. Well, I won't steal your thunder, then!
Q: It was a great talk.
A: Thank you.
Question 10
34:05
Q: Hi, I'm the token pre-mastication question. So you know, it goes: You know, you have your first baby and you sterilize everything before it touches her mouth and by the third baby you're picking up a pacifier and you're popping it in your own mouth before you pop it in theirs, and there was some concern about that in terms of, I guess, oral hygiene and what I had heard was, you know, it's not such a wonderful thing to introduce your mouth germs to your baby, but if your pre-masticating their food perhaps you disagree with that.
A: Yes. Yes. I suppose if you had something unhealthy going on your mouth, that would be a problem, but I — I don't really think that there's anything unhygienic about the mouth, if you're healthy.
Q: OK.
35:00
OK, well, thank you.
Acknowledgements
I've never given a talk to an audience of this size and calibre before. I particularly want to thank Sean Baker, Zooko Wilcox, and Jeff Pedelty for their support and encouragement in making it happen. I'm grateful also to the patient organisers of AHS for welcoming me and helping me through the process, particularly Katherine Morrison, Grace Liu, and Ben Sima.
References
