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Evolutionary Biologist Takes On 'Paleofantasies'

February 7, 2018 1:45 p.m.

Evolutionary Biologist Takes On 'Paleofantasies'


Marlene Zuk, professor, University of Minnesota

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This is a rush transcript created by a contractor for KPBS to improve accessibility for the deaf and hard-of-hearing. Please refer to the media file as the formal record of this interview. Opinions expressed by guests during interviews reflect the guest’s individual views and do not necessarily represent those of KPBS staff, members or its sponsors.

Paleo diet have been mainstream for years. The idea is that our genes are best suited to the foods our ancestors ate. Evolutionary biologists say we never stopped evolving, so paleo diet are not a cure-all. She teaches at the University of Minnesota but will lecture in San Diego tomorrow. She recently spoke with our producer.
>> I will generalize, but paleo diet's are high in meat and fruit and vegetable and lower in starches and dairy. You have a stance? Does biology tell us anything about these diets?
>> First you will get my standard caveat is -- and that is I am not a nutritionist and I did not write a diet book and I do not care what you eat. I do care, but most the, eat what you want. It is not that evolutionary biology gives us a prescription for diet. What I think it can do is tell us a bit about what we think is natural or a reasonable way for us to behave about food. You mentioned dairy. Dairy is a good example. It would be easy to say, people are not meant to eat dairy. Humans have evolved an ability to tolerate milk. We understand how the process happened better than we understand the evolution of a lot of other characteristics that humans have. And so, people change in the way that they eat things, just like they have changed in the way we move and they have changed and lots of other aspects of our biology. What I am fascinated by is this belief that we need to go back to the old days because that is how we evolved. That is not true.
>> Diets -- a lot of people who are proponents of paleo diet's look at agriculture and when humans started growing crops as a turning point. You have said that there has been an effective agriculture on human disease and malnutrition. Are there things that we can learn about health by looking back at evolutionary heritage is?
>> Absolutely. Evolutionary biology is the way I make my living. I will not tell you not to think about evolution because I think it is the most important thing in the world. But, that does not mean that there is a single period in our history when we were eating or taking care of our children were sleeping in a particular way that is somehow the best for us. I think a lot of it reflects the idea that somehow we got to this point in evolution where we reached a pinnacle and we were perfectly adapted to our environment and everything was in harmony and life is beautiful and then along came nasty agriculture and we started working too hard -- then it all led to big Macs and obesity. That is not true. There was not one period in human evolution when we were anymore in perfect harmony with our environment than any other time .
>> You mention earwax as an example. What does that have to do with evolution?
>> [ laughter ] that is the thing that is a relief to talk about other than diet. People get passionate about what people should he. The idea is that there are genes that control the kind of earwax that you have. I was fascinated to discover this when I did research for my book. There is a wetter form of earwax and a drier form of earwax. People speculate that people from certain parts of the world have one kind and they may be adaptive in shielding our ears from damage -- it is a great example to think about how there are small things about our bodies that we do not consider that also may be subject to natural selection and have evolved in lots of different contexts. The other point is that something you may think is a great thing to have from the standpoint of evolution and it may work in some environments and not others. What kind of earwax you have may be helpful in some places but not others .
>> The research you have done, does it give you a sense of where the human body is headed?
>> I have not done research that says this, but other people have. It depends on where you live and what you are selection pressures are like. But of the most interesting things coming out in the net -- in the last few decades is that you can study modern humans and look at who has more children. That will show you where genes are likely to become more prevalent and which ones are likely to die out. There was a study don't -- done in Massachusetts and a biologist named Stephen Stearns led a study that showed, assuming conditions continue the way they have been over many decades, women, they focused on women, they are getting slightly shorter and slightly fatter. Pressure is going down. We can see that this is a direction that things are going and. Not a gigantic change. When people ask me that, they expect me to say yes, we will be brains and fats in 20 years. I cannot say that. But smaller, fatter -- lower blood pressure, not so bad.
>> She will be speaking tomorrow at the Scripps institution of oceanography.