Looks like Daniel Lieberman, professor of human evolutionary biology at Harvard, has a new book coming out next week: The Story of the Human Body: Evolution, Health, and Disease.
As part of the pre-release publicity, he did an interview with The Guardian on why, given an evolutionary perspective, “diet and exercise really do matter.” Re obesity and the mismatch between how our bodies adapted to evolutionary pressures versus our modern environment:
We evolved to put on fat wherever necessary, and that was a good thing in human history. Most people until recently had to work hard and they lived just at the margin of energy balance, and a little bit more energy stored in fat meant that you could have more babies, and your babies were more likely to survive. That was pretty powerful stuff, right? Now we’re in this bizarre situation that for the first time in billions of years of evolution we have an organism that is not energy limited any more.
Why dieting “is a disaster” for us:
it takes superhuman effort to lose weight, it can be done but it isn’t easy. And that’s because we’re evolved not only to gain weight but to hold onto it. So if that overweight person starts dieting that’s just as hard as if an underweight person starts dieting, you go into a negative energy balance and all kinds of mechanisms kick in that cause us to become less active, to reshuffle energy around our bodies to defeat that effort to lose weight.
While he wrote the book to point out the problems, he’s not particularly optimistic:
The current gaze into the crystal ball doesn’t fill me with optimism. … So for example the US rates of childhood obesity have levelled off, so everyone’s patting themselves on the back. In actual fact they’ve levelled off to unacceptable rates and most of those kids who are overweight or obese have a much higher possibility of suffering a wide range of diseases. China has had a tenfold increase in type two diabetes. India’s a time-bomb of diabetes and obesity. The list goes on – Mexico is more obese than America. So I think the future of our planet is a lot more overweight people with a lot of very costly chronic diseases that will never be easily treated. So unless we really grapple with helping people change their diets and get them to be fit, these problems will continue to mount and cause economic woe and increased suffering.
I’m not sure that Lieberman’s book is going to be enough to stop the train wreck (I too am worried things are going to get far worse before they get better). In particular, I’m not on board 100% with what he’s described in the past as “socially acceptable coercion” as the public health strategy he recommends.
But I do think that understanding the problem is a pretty good first step. And his contribution is a big one over the traditional “eat less, move more” personal responsibility viewpoint.