Another entry in the Jacobs formula: he'll breeze through a large number of activities, giving very superficial descriptions & background, making wisecracks, and recording his wife's reaction to everything.

The problem with this one is that ultimately, all his health interventions are lame. Tim Ferris may be a huckster, but at least in 4 Hour Body, he put himself out on the edge and wrote about interesting things which might make real differences if they panned out; while Jacobs recycles crunchy granola nonsense and works his way through a bunch of boring and tired interventions and foods, many of which could never make any large difference in his health or longevity even if true.†

He has no ambition or bravery at all: I was disappointed that he was scared off by caloric restriction and wouldn't even give intermittent fasting a try (despite alternate-day fasting being probably the simplest diet ever), and when he finally does try something a little more drastic like Clomid for testosterone deficiency he seems to abandon it as fast as he possibly can despite admitting that it seemed to be more effective than pretty much anything else. This is a general trend with everything he reports back on: he drops them as fast as possible, without giving them a fair shake.

I mean, I don't believe that, say, fruit juice fasts work but if Jacobs is going to try then, couldn't he at least stick it out more than 3 days? I felt he was wasting both his and my time. (That said, I am amused to find out just how many eccentric exercise classes apparently can be found in Central Park over the course of a year.) Chapter 19 was on sleep, a subject near and dear to my own self-experimenting heart, so I had great expectations, and was disappointed to see that it boiled down to 'get a CPAP for snoring' and apparently using his brand-new Zeo less than week. Or on the topic of driving and walking helmets, whose net benefit I found myself uncertain of after reviewing some of the research literature, he brings them up but dismisses as impossible, not because they don't seem worthwhile, but because they would be too embarrassing - Jacobs, seriously, are you a man or a mouse? (The only things he seems to really stick with is his treadmill desk - well, fair enough for a writer - and, weirdly given his terror of embarrassment, noise-canceling headphones. As if the photos of the headphones didn't make him look like he was autistic...?) Some gaps just struck me as odd: why would a germaphobe look into squat toilets and wash his hands excessively, but omit any consideration of bidets which could remove most of the reason one would need to wash hands?

Perhaps unsurprisingly, I reached the final chapter and was distinctly unimpressed what his two years of effort had wrought:

I went for my final exam at EHE and found out I’d lost another half pound, ending at 156.5 (total weight loss: 16 pounds). I’d gone down two belt sizes. Dr. Harry Fisch told me that my lipid panel numbers “are so good, they’ll give you a heart attack” (HDL: 48, LDL: 62). I more than halved my body fat percentage. I can now run a mile in less than seven minutes as opposed to not at all. I have a visible chest.

One might think that such results, while laudable, did not require 2 years and probably were entirely due his eating less and spending some time weightlifting and running.

The evaluation of research is also weak. Jacobs promises in the intro to draw as much on the Cochrane Collaboration as possible (fantastic!) but if he did so in the rest of the book, I must've missed it (boo, hiss). And while it's a tired, sometimes overused truism in my parts of the Internet that 'correlation is not causation', Jacobs is one of the people for whom that dictum was meant.

Aside from the main storyline of the latest health fad, Jacobs counterpoints the slow death from old age & dementia of his grandfather and the unexpected death of his eccentric orthorexic aunt. These are good reminders of the horrors of aging but while well intentioned, Jacobs, superficial and middle-class humorously as ever, is unable to bring out the tragedy of the material anywhere near as well as, say, Still Alice, Do No Harm, or even blog posts like "Who By Very Slow Decay".

So what's good? Well, Jacobs is intermittently funny. He does go through a wide range of interventions, which is mildly interesting, and if nothing else, makes the point that there are a lot of hucksters and idiots and people fooled by randomness out there, and that there is no nostrum that will not put someone on cloud nine nor silver bullet so silly that it will not sooth someone's sickness. For me, it functioned as reminders (the accident chapter reminded me that after a slip in my bathroom, I had meant to buy anti-slip pads, which I've put on my shopping list; his treadmill usage has inspired me to clean off my own treadmill desk and at least use it while watching movies or playing games; I had heard of the potential benefits of squat toilets but until reading the FAQ by the guy selling them I had not realized that it was possible to retrofit regular Western toilets to be squat toilets, so I may grab some cinder blocks & plywood and give it a try; and his own conspicuous failure to try out IF makes me feel more motivated to give it a try myself soon, especially now that I've got daily blood glucose measurements debugged). So it wasn't all bad.

† To elaborate on this one point: we don't have hard precise evidence on most of the claims covered in the book, but for a lot of them we can give upper bounds on maximum possible benefits. For starters, lifespan is in humans, as it is in other species, partially heritable, so about a quarter of variability is off the table from the getgo. And no one has ever lived longer than Jeanne Calment's 122 years while life expectancy for Jacobs is ~80 (above-average since he's an employed well-educated white man with good family longevity), so he couldn't expect more than 40 years for anything that past humans have tried. Similarly, because of the exponential increase in death risk with age, the value of preventing any given disease in old age is not as high as it may seem, since if you prevent a heart attack, they may just die of a stroke or Alzheimer's instead, which sharply limits how valuable any particular intervention could be. So for example, if you could prevent cancer in its entirety, I've seen estimates that this might add a grand total of 10 years to average life expectancy, which is much less than one would expect; Jacobs quotes one person as noting there's something like 50k industrial chemicals out there; so if all cancers were caused by a modern industrial chemical, and you could eliminate each chemical completely for free at the cost of a day's research or work or income, then doing so would be... a huge net loss since 50,000 days >> 10 years (3,652 days). Not to mention that adult life expectancies have kept increasing hand in hand with the proliferation of industrial chemicals, suggesting that all of them together can explain only a fraction of variance. If you spend a day worrying about Bisphenol, you'd better have good reasons for thinking it's very likely to be harmful, because the prior probability is low, the harm is likely fairly minimal, you can't do much about it, and what you can do is expensive.