Evolutionary Weight Loss or: Why Weight Loss Sucks

Stephen Decker
Aug 28, 2017 · 4 min read

Weight loss is not desirable in an evolutionary context.

I repeat: Weight loss is not desirable in an evolutionary context.

Got it? Good.

Evolution is interesting to contemplate, which is why I think the physiological sciences are so amazing. Literally everything has to be viewed from an evolutionary context. Which brings me back to weight loss.

Weight loss in the context of evolution is typically involuntary. I don’t think I’m creating any novel ideas here, I’m just stressing something that I think a lot of people misunderstand. Weight loss throughout evolution wasn’t due to dieting — it was due to starvation — and the body does everything it can to protect itself from starving to death.

Case in point: Minnesota starvation experiment. N.B. this was before the era of IRB. This would be extremely interesting to do with the technology we have today, but probably very, very risky and unethical.

http://jn.nutrition.org/content/135/6/1347.full.pdf+html

This study was designed to mimic the brutal conditions of German WWII imprisonment by restricting subject’s caloric intake to about 1500–1600 kcal/day and increasing physical activity to 3,000 kcal/day (or, as the authors note here, about 22 miles of walking per day) for 6 months. For you CICO people, that’s a net caloric intake of -1500 kcal/day for half a freakin’ year!

Did they lose weight? You bet. The goal of 25% weight loss was achieved. Note that these subjects were not overweight to begin with.

http://www.curezone.org/forums/am.asp?i=1430817

And this is how they looked:

http://www.bbc.com/news/magazine-25782294

Essentially the study started with people that were roughly normal weight (150 lbs or so) and finished with people weighing about 100 lbs. That’s only about 10 lbs more than my great-uncle Frank weighed after his German POW imprisonment.

Not only did the subjects lose weight, they also became obsessed with food, developed psychological problems, and lost desire for other things (sex, activity, etc.).

http://www.curezone.org/forums/am.asp?i=1430817

But what I want to point out is that the graph above shows a slowing down of weight loss in the later part of the starvation period. The body adapted. In addition to all of the crazy weight loss, it was also noted that the subjects lost a lot of muscle mass, and the researchers even thought the subjects may have lost more muscle than fat.

This is important to understand in the context of evolution. The body’s main goal is survival at any cost. Usually in nature, the species that is most apt to store and maintain energy (i.e. fat) to prepare for the ever-coming but immeasurable starvation period were the ones to survive the best. Thriving, on the other hand, was rarely an option. Now that we live in a time where fasting and weight loss is typically done out of consciousness rather than circumstance, we need to take this evolutionary context into great account.

The body doesn’t want to lose weight. Ever. And it will fight weight loss as much as it can by slowing metabolism, curtailing reproductive organ activity, inducing lethargy, and a host of other physiological phenomenon. This is why weight loss is difficult as hell.

Evolution works, and we can’t change that. Diurnal metabolism is probably the effect of a lot of this. This brings me back to a point about eating in mornings and fasting at night: If humans were more likely to eat in the evening (which makes sense, logically), then it would also make sense that they would want to store fat more efficiently in the evening [to store energy for starvation!] via reduction in insulin sensitivity. Surviving ≠ Thriving. Maybe to survive, humans had to eat later in the day. To thrive, it may be best to fast later in the day and eat earlier.

For weight loss, though, evolution has made things tough to manage. The body adapts as best it can to store energy, which in the context of evolution is a net benefit. It does make losing weight suck, though.

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