Over the past twenty years, evolutionary biologist Herman Pontzer has conducted ground-breaking studies across a range of settings, including pioneering fieldwork with Hadza hunter-gatherers in northern Tanzania.
This book draws on his eye-opening research to show how, contrary to received wisdom, exercise does not increase our metabolism. Instead, we burn calories within a very narrow range: nearly 3,000 calories per day, no matter our activity level.
By taking a closer look at what happens to the energy we consume, Pontzer explores the ways in which metabolism controls every aspect of our health – from fertility to immune function – and reveals the truth about the dynamic system that sustains us. Filled with facts and memorable anecdotes, Burn will change the way you think about food, exercise and life.
I saw Herman Pontzer’s New scientist lecture on metabolism earlier in the year and thought I’d buy his book because it sounded interesting.
It was okay.
I enjoyed the sections on the Hadza, a rare, surviving hunter-gatherer culture in Tanzania, and his research on metabolism constrictions, especially the comparison work among apes and other mammals, and discussion of the causes and effects of the differences in metabolic rates and constraints. The human body really is amazing. I found the details about life for hunter-gatherer and hunter-horticultural groups fascinating. The author is an anthropologist, so his work in this area is excellent, well-thought out and written with liveliness.
It is unfortunate that he should then go on to discuss humans who don’t live like hunter-gatherers so negatively. He rather romanticises the Hadza and their way of life, especially in the final chapter, while excoriating people in industrial cultures for being lazy and eating too much processed food. He is following the path of so many in blaming all the worlds ill on the greedy fat people for using too much fuel and taking up too much space. Apparently he thinks the ‘obesity epidemic’ and climate change are equal in their threat to human existence.
What ‘obesity epidemic’?
Obesity isn’t a decease, it’s a medical, pathologizing word for fat people. There have always been fat people, because humans come in all shapes and sizes. There are more tall people now than there ever were before, but we don’t have a ‘tallness epidemic’. They have the same cause too – more people are living for longer and fewer are starved of nutrients as children. Having access to food in relative abundance means that you’re more likely to survive and thus grow to your final size and shape.
It is also a made up classification, based on a 19th century astronomer’s eugenics project to prove that the European population is ‘fitter’ than any other. The originator of the BMI scale never intended it to be used for individuals. Pontzer relies heavily on the BMI information for his claims, even showing a graph of percentage of people with ‘obese’ BMI against sugar consumption. Sugar consumption has decreased but BMI continues to increase. There are two data points before 1990 and half a dozen after 2000, with a turning point in 1989/90 when there is a dramatic increase in the percentage of the US population scoring obese on the BMI scale.
In 1989 the BMI groupings were shifted by five points so people went to bed slightly overweight and woke up morbidly obese. This is change was to increase the influence of drugs companies and weight loss companies, encouraging insurance companies and doctors to prescribe weight loss and weight loss drugs. At no point does Pontzer address this in all his screeds against fat people.
He also continues to reinforce the narrative that obesity is a disease, and a cause of death and cardiometabolic diseases. There is a correlation but no one has yet shown a causative link between being fat and being diabetic, for example. It is only assumed to be the case without taking into account many, many confounding factors, such as genetics, socioeconomic status, stress levels, a history of weight cycling, etc. Pontzer is an anthropologist with an expertise in metabolic constraints, he is not a nutritionist, a medical doctor, a cardiologist, or anyone who does have the expertise to talk about medical matters.
His final chapter on the future continues his fatphobia, but also waxes lyrical about how he thinks humans need to change to survive. There is an awful lot of scholarship and research on this subject and it looks like he’s read the popular press versions and then added his own ‘be like the Hadza’ spin.
If the author had written a memoir about his time with the Hadza and his years as a researcher, that would have been great. He really has a flair for bringing his experiences to life. If he’d wanted to write a popular book about his research in to the metabolism as it applies to humans, other apes, other mammals and the constraints of metabolism on life, that would have been fantastic. But he didn’t, he tried to write something that is both and a blast against fat people and industrialised society, and failed to do well the things he could have done well at all.
Some if this book is worth reading but still slightly disappointing at times.