What to expect this week:

Rates of obesity are skyrocketing. Why is this?

The easy explanation is that we have more access to cheap, calorie-dense food than ever before. However, that is only half of the story. The other half involves our evolved tendency to store fat.

Check out this week’s video to get a better idea of how our modern culture interacts with our ancient biology to produce the obesity epidemic of today.

Housekeeping:

I know that I’ve been rotating the same couple of songs in my videos, but I’m working on finding the time to create some more. It’s quickly becoming one of my favorite parts of this whole creative endeavor I’m on. Can’t wait to have a lengthy discography of songs to spice things up for you guys.

Links to my e-Courses

• The Bare Minimum - FREE

• The Adaptive Scholar - $5

Obesity is a Disease of (OUR) Civilization

Obesity itself is not new. Humans have come in various shapes and sizes since the dawn of our existence. Unfortunately, soft tissue does not fossilize and is rarely preserved under the ground. This makes it difficult to find direct evidence of overweight humans in the ancient past. However, we do have some indirect evidence. 

Some of the oldest stone statues archaeologists have discovered are small artifacts known as Venus figurines. They are scattered across Eurasia and date to the Upper Paleolithic period (around 25,000 years ago). What’s so fascinating about these statuettes is how they depict women, typically unclothed, exposing large quantities of visceral fat. This doesn’t imply that this was the typical human form of the populations that made them, but rather that obesity was not completely foreign to them.

Ancient historical texts also suggest that obesity existed before the modern industrial era. The Greeks understood the dangers of obesity. Hippocrates in particular (who lived around 400 BC) warned of the dangers of overeating and even suggested that being obese increased your likelihood of sudden death [2]. Other traditional cultures around the world have believed that being overweight is a good thing - that it is a sign of wealth and social status [3].

What’s pressing about obesity is its prevalence in modern-day society. Although it has always existed, it has never been as widespread as it is today. Here are some statistics from the World Health Organization that might help put this in perspective [4]:

• Worldwide adult obesity has more than doubled since 1990, and adolescent obesity has quadrupled.

• In 2022, 2.5 billion adults (18 years and older) were overweight. Of these, 890 million were living with obesity.

The WHO also cited some reasons for what causes obesity. They say it often results from “an imbalance of energy intake (diet) and energy expenditure (physical activity),” but that in most cases, it is a multifactorial issue. For example, many people today grow up in obesogenic environments, where calorie-dense nutrient-poor foods are very accessible, but healthy alternatives are not. 

One factor that the WHO did not include is our evolutionary history. On this channel, I discuss how insights from evolution can help inform our understanding of human health. In some cases, this means that straying from our evolved heritage can lead to suffering. In other ways, studying evolution can show us how it has set us up for failure. Obesity is a combination of the two. 

The Evolution of Fat

Body fat is not inherently bad. In fact, it is necessary for survival - especially in wild settings. Organisms need energy to perform basic physiological tasks, like keeping their heart beating or communicating with another creature, to stay alive and reproduce. That energy is derived from food and it comes in three forms - proteins, carbohydrates, and fat. 

Protein is rarely used for energy because it is so necessary for structural purposes, like building and maintaining muscle fibers. It is the last resort if there are no carbs or fat left. Carbs are a fast source of energy that the body has on speed dial and fat is the body’s way of storing energy for later.

Depending on a species’ physical characteristics and lifeways, it may require more or less energy. Humans have traits that require more energy, making us more susceptible to storing fat. Evolutionary anthropologist Herman Pontzer has shown that humans expend more energy per day than our primate relatives, like chimps, gorillas, and orangutans [5]. 

He and his colleagues suggest that:

They also tested body fat percentage and found that the average human holds more body fat than these other three primate species. This confirms work previously done by Zihlman and Bolter, showing that male and female humans both have more body fat and less muscle mass compared to their bonobo counterparts [6]. 

Having discovered this, they came to a similar conclusion as Pontzer, arguing that traits such as our large brains, reproductive habits, and even our bipedal foraging strategies all pressured our species into being more efficient at storing energy as fat. 

The Obesogenic Environment

The nature vs. nurture debate is a false dichotomy. Most outcomes are the product of the intersection of both. The modern state of obesity is a great example. In terms of nature, our bodies have always been genetically programmed to consume food and store it as fat. As for nurture, modern Western civilization can be viewed as an obesogenic environment that incentivizes eating more calories than we expend. 

The “obesity epidemic” of today is the product of these two factors, but it is the nurture side of things that has really brought it to a boil. 

While it is true that obese people likely always existed, they comprised a small percentage of the population. Research has shown that people living traditional hunting and gathering, pastoralist, and horticulturalist lifestyles have lower BMIs, waist circumferences, and tricipital skinfolds (which are used to measure body fat percentage) [7]. 

Obesity was rare in pre-modern societies, especially compared to the 43% of the adult population who is now overweight and 16% obese [4]. Some people argue that it was the Agricultural Revolution that initiated this, by making domesticated carbs our primary source of energy. 

However, we don’t see these dramatic increases in obesity until about one hundred years after the Industrial Revolution, when processed foods became the bulk of our diet. Some of the most fascinating videos you can find on the internet, especially for history buffs, are those depicting life in the late 19th and early 20th centuries. 

For example, people have salvaged and colorized footage filmed by the Lumière Brothers in 1896. This video shows people from all around the world going about their daily lives in public spaces. One thing that I notice in every one of these videos is the lack of overweight people. Sure you see one here and there, but compared to walking down the streets of New York in 2024, it’s barely comparable.

Anthropologists and others in the social scientists have used the term “civilization disease” to describe the obesity epidemic, suggesting that it is, at its core, the product of society. However, as we saw in the footage from 1896, those societies did not suffer from such a problem so pervasively. 

It’s not that civilization brings about the disease of obesity, it’s that our civilization does - our modern Western society. Our genetic predisposition to store more fat than typical for a primate did not become a serious problem until we introduced large amounts of processed foods into our Western diets. 

If you want more information on this transition to processed foods, in addition to a possible alternative that you can implement, check out my video on the Paleo Diet here.

References:

[1] Eknoyan, G. 2006. “A history of obesity, or how what was good became ugly and then bad.” Advances in Chronic Kidney Disease 13(4):421-7.

[2] Marghoub, S., et al. 2023. “Obesity from a sign of being rich to a disease of the new age: A historical review.”  6(11):e1670.

[3] Brown, P. 1991. “Culture and the evolution of obesity.” Human Nature 2(1):31-57.

[4] https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight 

[5] Pontzer, H., et al. 2016. “Metabolic acceleration and the evolution of human brain size and life history.” Nature 533:390-392

[6] Zihlman, A., and Bolter, D. 2015. “Body composition in Pan paniscus compared with Homo sapiens has implications for changes during human evolution.” Proceedings of the National Academy of Sciences 112(24):7466-71.

[7] Carrera-Bastos, P., et al. 2011. “The western diet and lifestyle and diseases of civilization.” Research Reports in Clinical Cardiology 2(2):2-15.

[8] https://www.youtube.com/watch?v=DDi62bPbWHw

Fit Fuel Song Suggestion

The Fit Fuel song suggestions are hand-picked by yours truly to elicit the motivation (and possibly aggression) needed to initiate or persist through a grueling workout. They consist of heavy, brutal guitar riffs and gruesomely guttural vocals. Additionally, I timestamp what I believe to be the best riff of the song - one that will kick your nervous system into overdrive when approaching a personal record (PR).