I'm chiming in just to say that I'm really enjoying the new book,
Burn, by Herman Pontzer.
I pre-ordered it a while ago because the subject seemed interesting. By the time the book came out and was automatically downloaded to my kindle, the subject didn't seem as interesting anymore.
But I started reading it anyway and am enjoying it a lot more than I expected to. The subjectÂ
is interesting, and the book is unusually well written.
It's about metabolism. The basic idea is that exercise doesn't matter for weight loss as much as you probably think. Exercise is extremely important for health, just not necessarily for weight control. Weight loss is all about calories in versus calories out, but a really unexpected finding -- now confirmed in numerous ways -- is that exercise doesn't actually affect "calories out" all that much. I mean, during a particular exercise session, "calories out" increase as much as we'd expect. When you do work, you have to burn the appropriate amount of energy to cover it. But if you start exercising regularly, your body weirdly slows down its metabolism during your non-exercise periods, like during sleep. So the total number of calories you burn throughout the entire day is somewhat constrained -- once you get beyond a certain threshold, more exercise doesn't translate into much more total energy expenditure after accounting for the more efficient metabolism habitual exercisers enjoy while at rest. (I think what's going on is that when non-exercisers are at rest, their bodies are still working hard at the cellular level to mechanically deliver nutrients to cells, to clear waste from cells, etc. But a lot of that stuff happens automatically during exercise, so habitual exercisers can truly relax at the cellular level when they're just sitting around, in a way that non-exercisers cannot. But I'm just guessing at this part, not having finished the book.)
Anyway, in addition to popularizing some surprising findings (that the author worked on firsthand over the past few decades, getting Hadza hunters to drink doubly labeled water, for example), the book covers the traditional basics of metabolism in a very readable and interesting way, so the non-surprising sections are highly recommended as well.