Wow & Yahoo!! Scientific American on Exercise & Weight Loss


I get a lot of flak about my life style of Non-Exercise. For some reason, it causes anger & resentment among many I know. It is one of the reasons that wives, even those who are my friends, warn their husbands to not spend much time with me.

This week, I got my own personal “don’t blame them for they do not know what they say” moment. And it came courtesy of a friend & reader who is actually a committed exerciser.  She sent me the recent issue of Scientific American with a cover story that explains why physical activity does little to control weight. Say What?

After all, the article itself cites conventional wisdom:

  • “It seems so obvious and inescapable that physically active people burn more calories that we accept this paradigm without much critical reflection or experimental evidence”

But what about critical reflection of public health experts? The article says:

  • “Researchers in public health and human evolution have long assumed that our hunter-gatherers burned more calories than people in cities and towns do today. … Many in public health go so far as to argue that this reduction in daily energy expenditure is behind the global obesity pandemic in the developed world.”

So who are these guys who say otherwise and what is their evidence? The author is an anthropologist from Hunter University who, with two colleagues from Yale & University of Arizona, “spent the past month living with the Hazda, traditional hunter-gatherers in Northern Tanzania“. They made “a couple of dozen Hazda men & women drink small, incredibly expensive bottles of enriched in two rare isotopes, deuterium and oxygen 18“. Analyzing “the concentration of those isotopes in urine samples from each participant allowed them to calculate their body’s …. daily energy expenditure” – an approach labeled as “the gold standard in public health for measuring the calories burned each day during normal daily life“.

What did they find?

  • Our data indicate that, contrary to received wisdom, humans tend to burn the same number of calories regardless of how physically active they are. 


  • the new science helps to explain why exercise is such a poor tool for weight loss. It is not that we are not trying hard enough. Our bodies have been plotting against us from the start“.

This new science of metabolic adaptation examines a constructive, adaptive metabolism that has enabled humans to flout a “bedrock evolutionary principle”.

  • “Our brains are so large, that as you sit reading this article, the oxygen from every fourth breath you take is needed just to feed your brain. … the critical changes that make us human were fueled by an evolutionary shift in our metabolic engine“.

The article discusses human traits like sharing food & other “unique and essential part of our evolutionary inheritance” such as “human imperative to work together“. But what intrigued us the most is the line below: 

  • “the faster reproduction and other expensive traits of humans were linked to the evolution of an increased metabolic rate“. 

Men, to the best of our knowledge, do not actually reproduce but merely contribute to the task of reproduction. And the human race cannot reproduce without such contribution from men. Women, with modern methods, can decrease the rate of reproduction of the human race but they cannot increase that rate. Ergo, the frequency of contribution from men is directly proportional to the evolution of an increased metabolic rate? 

But does that work on an individual level? We have shown that a lifestyle of Non-Exercise can lead to or co-exist with a Zero Plaque score in Cardiac CT scan. But what about increased frequency of male method of contribution to reproduction? Does that also lead to higher metabolism or a lower score of plaque in arteries? After all, isn’t “intercourse” definitionally equivalent to the “human imperative to work together“?  

Since our plaque score is already Zero, we cannot reduce it further from such experimentation of “increased frequency” of male contribution. So we sadly have to leave that experimentation to others. How painful are the penalties of perfection?


PS: Folks, we admit we yelled Yahoo when we read the above article. And we always sing the Yahoo song below when we say Yahoo. And we have been called “junglee” (or primal) on occasions. And yes, this song led Jerry Yang, the founder to name his company Yahoo!



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