On this episode of The Torch, we examine what food science can really teach us about the health implications of what we eat.
Here to discuss, “Food, Science, and the Human Body” is Alyssa Crittenden, Professor of Anthropology at the University of Nevada, Las Vegas.
This transcript has been edited slightly for readability.
The Great Courses: Eating is as old as mankind, are we really still learning about the foods we eat?
Alyssa Crittenden: Absolutely, more than ever.
The Great Courses: Why? How is that? What tools does science have now that we didn’t have 10 years ago?
Alyssa Crittenden: That’s a really good question. I’m a nutritional anthropologist, so my lens is a little different. I’m really interested in human evolution, and I’m interested in how humans evolved with our food. I am really interested in the story of nutrition from the beginning, so starting close to three million years ago until right now today, and into the future.
Paleo Diet vs. Paleolithic Diet
The Great Courses: All right, let’s talk about the paleo diet, because that goes way back, right? A lot of people talk about the paleo diet, it’s eating like our cave brethren ate.
Alyssa Crittenden: Right, that’s the idea.
The Great Courses: Describe it correctly.
Alyssa Crittenden: Okay, so there’s a big distinction to make, and this is something that I think is important, not only for people that want to start a paleo diet, but also just for people that are generally interested.
There’s a difference between the paleo diet, which is the dietary practice and kind of lifestyle that most people today, in the 21st century are practicing, and then there’s the paleolithic diet, which is the diet that is what our ancestors were eating.
They’re not always the same, but the basic idea is that the paleo diet is very meat-centric, it’s very protein heavy. There are pros and cons to that diet.
I can tell you what we know now, based on the evidence is that it turns out that the actual diet during the paleolithic was far less meat heavy than some of the paleo diet models would suggest. We actually evolved to be omnivores.
Learn More: Paleo Diet and Ancestral Appetite
We evolved to eat a diet that’s composed of plant and animal material. For some people, the paleo diet really does work, and that’s wonderful. It’s important to remember though that most people that are practicing the paleo diet are not attempting a historical re-enactment, they’re not actually trying to be paleolithic.
The Great Courses: No, they’re trying to do a trendy weight loss.
Alyssa Crittenden: Well, they’re trying to, I think, eat healthy foods.
The Great Courses: Is that healthy? It’s not balanced, per se.
Alyssa Crittenden: It depends on who you ask.
The Great Courses: Does it matter on the individual?
Population Adaptation
Alyssa Crittenden: It does, it certainly does. There’s all sorts of individual factors that make certain diets healthier. We talk a lot in the course about the interaction between food and genes, that plays a big role. Certain populations are specifically adapted to metabolize foods differently.
The Great Courses: Give us an example.
Alyssa Crittenden: Okay, I can give you a very interesting example that came out recently in the scientific literature, where the Inuit of Greenland have actually evolved. They eat a lot of Omega-3 fatty acids in their diet, many more than any other population on Earth.
They live in arctic conditions-and so they eat a lot of these Omega-3’s, which can have some kind of downstream negative consequences. They’ve evolved an ability to essentially buffer those negative consequences.
You asked a question earlier about, “How can there be so many changes?”, the whole system is changing. We are changing in the system, we have new diseases that are linked to what we’re eating, food has changed our evolution.
What we are doing with food is in turn changing our biology. We have new technologies, so food is changing, and we are changing along with it.
Our fellow partner in human evolution has been our diet, and they’re intricately tied. Back from the beginning up until right now, this is why this course is so exciting is because you can literally track it from the beginning of our species, and we’ll never even finish all the topics.
Our fellow partner in human evolution has been our diet. Click To TweetThe Great Courses: That’s fascinating. I looked through the topics and I was blown away, I was like, “Oh, I want to talk about that, I want to talk about that one, want to talk about that.” You have done some interesting work with some tribes in Tanzania, can you talk about that a little bit?
The Hadza
Alyssa Crittenden: Yes, I work with a group of hunters and gatherers in east Africa, in Tanzania, called the Hadza. I have been working with the Hadza for 13 years, and they are one of the last groups on the continent of Africa that are still foraging for the majority of their diet.
There’s a subset of them that are getting most of their food every day from wild food. They’re kind of making their living, their food economy, off of the environment, so wild plants, wild animals.
The Great Courses: You say they’re one of the last peoples doing that. What do you learn from them? Do they have an immense diversity to their diet, do they eat more of one thing than another? I’m told they have a lot of different kinds of meats that they eat.
Alyssa Crittenden: Yes. The reason that I became interested in working with foragers to begin with is that they’re often recruited as kind of a model for human evolution. Well, we know now there are some caveats that have to be made, so they are by no means a stone age population, they are just as modern as you and me.
They are a contemporary population. That being said, they live a lifestyle that is the most similar to our paleolithic ancestors, they’re nomadic, they eat wild foods, they don’t tend any crops, they don’t herd any animals, they don’t have access to birth control or antibiotics, so they’re living a lifestyle that allows us to ask some really interesting questions about how we adapted to our diet.
That’s one of the reasons I began working with the Hadzas, I was interested in looking at their food and kind of researching this food economy, and figuring out if it could tell us anything about human evolution.
The Great Courses: Has it told you anything?
Alyssa Crittenden: So much, it’s told me so much. I think the thing that’s the most important is that what we’ve learned by working with the Hadza for decades and decades, and other populations as well, is that there is no one forager diet.
This also gets back to your paleo question, there was no one paleolithic diet, because they’re all based on variety and they’re based on ecological variation and what’s available in the environment that you live in.
Which makes sense when you think about it, but we wouldn’t really appreciate this diversity. You can’t really understand how important and critical this seasonal and ecological variation is until you go out there.
Insects: The Other White Meat
The Great Courses: Speaking of diversity, you have one lecture titled “Insects: The Other White Meat”.
Learn More: Insects the Other White Meat
Alyssa Crittenden: That’s right.
The Great Courses: Are you kidding me? Really?
Alyssa Crittenden: I am 100% serious. Insects are a fascinating topic, they’re something that I love reading about and teaching and writing about. Insects have been a part of our diet since the beginning, and most places in the world, insects are still consumed.
They’re a very good source of nutrition. We in the US are not really comfortable eating insects as part of our diet. Mostly that’s just because it’s culturally, it’s a taboo, but nutritionally they’re fantastic.
The Great Courses: Are they a meat?
Learn More: Insects The Other White Meat
Alyssa Crittenden: Sure, they’re an animal product. There’s a move, if you’re interested. A lot of the very high-end fine dining restaurants in the big cities in the US are starting to incorporate insects into their meals. I’m not sure, do you drink tea?
The Great Courses: Yes.
Alyssa Crittenden: Do you put honey in your tea?
The Great Courses: No, but there’s honey bits? You get some insect in your honey? Is that what you’re saying?
Alyssa Crittenden: No, but honey is actually bee vomit. Even though you think it might be crazy, everyone in this room has probably consumed regurgitated bee vomit at some point.
The Great Courses: Okay, moving on.
Alyssa Crittenden: See? I’m telling you, insects are a fantastic nutritional resource.
The Great Courses: That is cool. Probably cannot underestimate the impact of fire on food, right?
Alyssa Crittenden: When many people think about kind of the hallmarks of human evolution, one of the things they list is our ability to harness fire, our ability to control fire. It certainly did change the game, it certainly did change the landscape.
When that happened is up for debate, but what we do know is that when our ancestors began controlling fire, not only did it help with things like light and warmth or protection from predators, but it also changed our food. One thing that cooking can do is it can make food that would be indigestible, digestible. It can break things down.
I have to point this out as someone who’s interested in evolution of nutrition, cooking is one of our complex processing techniques that we evolved, and there are many others that are really fascinating and don’t get as much attention as cooking. They’re not as sexy as cooking, but things like pounding and winnowing and dehydrating and fermenting also were really important in our evolutionary past.
The Great Courses: Talk a little bit about food versus cuisine, did that also evolve?
Alyssa Crittenden: Food versus cuisine, depends on who you ask. The way that I make the distinction is when I’m teaching my students, we talk about food and nutrition in terms of what it does biologically, in terms of how it affects basically your body as a biological organism.
Then when we talk about cuisine, I tend to talk about food and culture, beyond the biological part of it. Everybody has to eat, and food does stuff that we need in order to grow and maintain our body, but cuisine is people’s, I think, kind of cultural relationship with food. It’s integral to a lot of different national identities.
It’s a very important part of how people construct their own identity. I think that they’re both equally important, but they’re kind of different sides of the same coin.
Microbiomes
The Great Courses: All right, let’s go back to the physical, let’s go inside the body. There’s a lot of discussion these days about the intestinal tract, the microbes that are in the gut. I think there’s a microbiome? What is that?
Alyssa Crittenden: There are many microbiomes. You have a microbiome of your eye, of your mouth, of your bellybutton even, there’s a microbiome. I am really interested in the gut microbiome. That is basically the colony of bugs that reside in your gut.
These are mostly bacteria, protozoa, that live in our body, in and on our body, I should say. What we’re finding is that those little guys, those little hitchhikers who live in our digestive system are really important, they’re very important to the overall health of the host, which is us.
The Great Courses: By the way, we’ve known about them for millennia, probably.
Alyssa Crittenden: Long, long time, yeah.
The Great Courses: Right, so again, I’m fascinated by the fact that science is still looking at things that have been hiding in plain sight perhaps, and learning new things about it. It’s crazy.
We’ve talked a little bit about, human beings have struggled with starvation, that’s an ongoing issue, in some countries where there is plenty, we face perhaps overfeeding, is that such a thing, is that an issue in some societies?
The Problem with Over Nutrition
Alyssa Crittenden: Yes. We’re in a really interesting time in human history right now, where we have two competing health epidemics. One is over-nutrition and one is under-nutrition.
Interestingly enough in the world we grow enough food to feed everyone. This is why the World Health Organization and the UN, and all sorts of aid organizations are now shifting the discussion of poverty and under-nutrition to kind of more geopolitical discussions.
Over-nutrition, also interestingly, these days also has some strong roots that are tethered to poverty, because you can have too much energy, basically, but you’re not eating a diet that is containing what you need nutritionally.
The Great Courses: I guess it’s eating low-quality foods. Is it fair to call some food low-quality?
Alyssa Crittenden: I think you can, yeah. I think that the issue is that we have a rise in things like all sorts of cardio-metabolic diseases, so rise in type two diabetes, atherosclerosis…
I mean you name it, all these cardio-metabolic health disorders are on the rise, and that has to do with over-nutrition. Particularly in the developing world, you have those things happening when people have shifted to a low-quality diet that is energy dense, which is not the same thing.
The Great Courses: Right, because that was the early solution for the starvation, right?
Alyssa Crittenden: Yeah, sort of yes. It’s such a deep and complicated issue, but basically what we’re finding now, back to what I was talking about earlier, where diet and our genes are kind of intricately connected.
There’s this fascinating new field that’s called the developmental origins of health and disease, or epigenetics. We now know that what your mother or your grandmother ate while you were in-utero can actually affect your lifelong health consequences as an adult, and maybe even your children.
That’s why I’m a scientist, that’s why I love what I do is that we’re asking the same questions, but we’re getting new answers. Because our methods are advancing we have more elegant ways of asking the same questions.
What your mother ate while pregnant can actually affect your health consequences. Click To TweetLearn More: You Are What Your Mother Ate
Genetically Modified Organisms
The Great Courses: Well, it comes across. Does the course cover GMO’s?
Alyssa Crittenden: Absolutely.
The Great Courses: It’s such a hot topic, the politics of food, all that stuff. Talk about that a little bit. Why do people fear genetically-modified crops so much?
Alyssa Crittenden: One interesting thing is, we have been manipulating plants for 10,000 years. So a lot of anthropologists distinguish between genetic modification, which could be animal husbandry or kind of the tending of crops that we’ve been doing for thousands of years, versus genetically engineered foods.
Genetically engineered foods, kind of trans-genetic modification, what you’re talking about, is when you basically take DNA and you extract it and stick it into something else. Let me give you an example.
A lot of crops are being modified in order to do things like combat disease or insects. Let’s say that you have a crop that is really prone to getting attacked by pests. You can actually take bacteria and inject it into the strain of that plant, which will make it heartier, and it’ll just make it more resistant.
The other thing is, you want to put those types of bacteria into plants so that they can protect themselves against pesticides, because a lot of farmers want to use pesticides and not kill the plant, that’s one type. There are some other crazy things.
This one’s kind of interesting. All of us have had the experience where we’re cutting an apple and it browns, so the oxidation process starts. There is currently an apple that is supposedly going to be coming on the market, they’re waiting for it to get approved, where the browning will no longer happen.
The Great Courses: Why should we fear that? Why do people fear that? Do you think we should fear that? That’s three questions in one.
Alyssa Crittenden: Well, I’ll answer as a scientist. I mean, it’s not up to me to tell people what they should and shouldn’t fear. What I think is important is to understand both sides of the argument.
Genetically engineered foods have the potential ability to feed the planet, and with an expanding population that’s estimated to reach close to 10 billion people by 2050, this might be an important part of the future of food.
Genetically engineered foods have the potential ability to feed the planet. Click To TweetOn the other hand, the reason people are worried about this is because we don’t know the long term health effects, although so far, the science shows that they’re fine for you health-wise, but we don’t know what those downstream long term effects will be.
We also don’t know what the environmental consequences will be, by essentially creating these new crops. We don’t know if there will be any kind of ricochet effect from that. That’s why people are worried.
The Great Courses: Is that the biggest challenge you see in the 21st century for food? Or are there others?
Alyssa Crittenden: Now I’ll answer personally, I think personally something that is very near and dear to my heart is trying to figure out how we are going to deal with systemic under-nutrition. That is something that I spend a lot of time thinking about.
There are so many people in the world who exist on a dollar or less a day, and don’t have access to nutrition. I think that will continue to be a problem, and we are also running out of space, space to grow food, both for us, and to grow food for the animals we eat. A lot of future technologies will have to figure out creative ways to address this issue.
