(I swear I didn’t mean these posts to coincide with Thanksgiving, it’s just a coincidence!)
Over the course of this series, we’ve learned that the energy expenditure of hunter-gatherers like the Hadza is not markedly different—when adjusted for body composition—than people living in wealthy, post-industrial societies like the United States, Japan and Europe: “as we see with the Hadza, daily energy expenditures are the same today in the industrialized world as they were in our hunter-gatherer past.” (B: 183) Therefore, it isn’t likely that the cause of obesity is us collectively not moving around enough or not getting enough daily exercise.
As we've seen, enthusiasm for exercise has exploded, to the point where it has become a multi-billion-dollar-a-year industry. Sports is woven into the very fabric of our lives now. “Working out” is part of our daily parlance. Yet obesity has climbed relentlessly upward the entire time, showing no signs of abating. Look at drug prescriptions and hospital wards—we're sicker than ever. A mountain of studies tells us that exercise alone is ineffective for weight loss:
Why you shouldn't exercise to lose weight, explained with 60+ studies (Vox)
So if our metabolism adjusts the amount of calories we burn to keep it in line with intake, then it must be that it can't keep up with the intake. Pontzer argues that the cause of obesity must therefore lie in what we put into our mouths, concluding: "If our bodies keep daily energy expenditure in check regardless of lifestyle, energy imbalance and weight gain must come primarily from eating too many calories." (B: 182)
But what is it about our food environment that is causing this to happen?
The conventional wisdom centers around food availability. There's just more food around than ever before. That's why we get fat.
But I find this answer to be unconvincing. Just because there's more food around, doesn't mean we have to eat all of it. We've already seen that we have very intricate and finely-tuned mechanisms to adjust our food intake, metabolism, and fat reserves in response to our energy requirements. We have built-in satiety signals that prevent us from overeating. We have physiological limitations on fat storage, modulated by our hormones. Even in our food-rich environment, we do not stuff ourselves to the point of death, even though we could theoretically do so.
In fact, even in our food-rich environment, most people's weight varies only a few pounds a year on average. Experiments have shown that it's actually quite difficult to pack on a lot of weight in a short period of time. We've also seen that overshooting (or undershooting) our caloric intake by as little as one or two percent a year would cause consistent weight gain (or loss) year after year. Yet despite this, we've seen that hunter-gatherers effortlessly maintain a stable weight throughout their entire adult lives during good years and bad.
And the notion that everyone, everywhere, was pretty much starving all the time right up until about the 1970s is also a bit hard to swallow. This is seriously argued by many people, including many scholars and historians. Of course, it’s true that we didn't have the hyperabundance provided by today's supermarket shelves and fast-food outlets in the past. But it's hard to believe that everyone, everywhere walked around with their stomachs constantly rumbling and empty all the time, always on the edge of starvation, unsatisfied and wanting more, for virtually all of human history until—in effect—the present day.
Sure, people went hungry in the past. Sometimes there were famines. But that's not the case for all of human history! If that were the case, it's hard to believe we would have constructed Stonehenge, the Pyramids, the Acropolis, the Colosseum, Hagia Sophia, the Gothic Cathedrals, the Taj Mahal, the Mayan temples, the earthen mounds at Cohakia, the Great Wall of China, or anything else for that matter. Those things take work, and work takes energy. That's simply the laws of physics: “Life takes energy. Every physiological task, every metabolic chore, burns calories.” (B: 287) If we didn't have enough energy in our bodies—that is, if most people in those societies were truly starving most or all of the time—then it's hard to believe they would have—or even could have—accomplished such things, or even created civilizations in the first place.
Instead, their minds would have been laser-focused on one thing and one thing only—getting more calories, every single day, day-in and day-out, to feed themselves. Starvation induces lethargy. We know this from the Minnesota Starvation Experiment, for example. But that's not what we see. The evidence is all around us. How can we ignore it?
We now know that the people who built these monuments did so by-and-large voluntarily—they were not inmates in concentration camps forced to work to the point of death. No biological organism can survive if it persistently expends more energy than it takes in—it would have been weeded out by natural selection. Humans are no different. Hunter-gatherers manage to meet their caloric requirements with only around 20 hours a week of work, giving them plenty of leisure time. Surely they would work harder than that getting food if they were still hungry day after day.
We've already seen Dr. Pontzer belittle and reject the Paleo Diet, along with several other popular "fad" diets. There is no particular class of food, he assures us, that is particularly bad for us or causes weight gain. There is no ideal macronutrient ratio for us to consume, he tells us, either now or in the past. He dismisses out of hand the increased consumption of carbohydrates or sugar as being the culprit behind obesity and diabetes. He cites the example of the Hadza diet—which is both rich in carbohydrates (such as tubers) and in simple sugars (in the form of honey)—as evidence:
The Hadza, Tsimane, and Shuar populations all get 65 percent or more of their calories each day from carbohydrates (compare that to less than 50 percent for the typical American diet)…Much of this carbohydrate comes from starchy vegetables, like the tubers that Hadza women often bring home. The other big source of carbohydrates is honey, which Hadza men and women consistently rank as their favorite food…If carbs—especially sugar—were particularly bad for you, these high-carb cultures should all have diabetes and heart disease. Instead, they have exceptionally healthy hearts and virtually no cardiometabolic disease.
Diets among populations like the Hadza, Tsimane, and Shuar are also low in fat, which makes up less than 20 percent their calories each day (the typical American diet is 40 percent fat). In fact, outside of the far north, there aren’t any well-documented hunter-gatherer groups (like the Hadza) or horticulturalists (like the Tsimane and Shuar) with diets that are high in fat. (B: 200)
Pontzer points out that our consumption of sugar has actually been declining for some time, even as obesity rates have risen. In the past, Americans ate more bread than they do today, and yet they were not fat. He also dismisses the notion that "calories don't matter"—that it is possible to lose weight without burning more calories than you take in:
...we should be suspicious of any diets that target one specific nutrient as a hero or villain for weight loss. Nothing is innocent if eaten in excess. Any calories that aren't burned, no matter if they come from starches, sugars, fats or proteins, will wind up as extra tissue in the body.
If you're pregnant or bulking up at they gym, that extra tissue might be useful things like organs or muscle. But if you're not, those extra calories, no matter their original dietary source, will end up as fat. That's the foundation we need to understand to begin talking about all the real-world complexities of the diet and metabolic health. (B: 54)
It's still the case that obesity is fundamentally a problem of taking in more fuel than our engines burn (B: 184)...there's simply no way that anyone is losing weight without consuming fewer calories than they expend, regardless of what those calories are made of. Those are the laws of physics...It's entirely possible to lose weight without counting calories, just like it's possible to drain your bank account without paying attention to your finances. But it isn't possible to lose weight without eating less than you burn. (B: 216)
The ultimate problem, he says, lies not on our body but in our brain. We usually talk about our stomach when it comes to appetite, but in reality our appetite and energy expenditure is regulated by our brain, specifically the hypothalamus. The hypothalamus controls both our appetite and energy expenditure to keep them in balance. But somewhere along the line, something has gone terribly wrong with this mechanism:
...our metabolism is tightly regulated by our hypothalamus, which constantly monitors the food we eat and the calories we burn to keep our bodies in energy balance. But something—or more likely, several things—about our modern environment is causing the hypothalamus to misfire, leading us to consume more calories than we expend. (B: 192)...rather than pretend we're in the driver's seat, we should be asking why the evolved mechanisms that normally match intake precisely to expenditure are failing in our industrialized world. (B: 184)
And so, in the end, Pontzer ultimately places the blame on the ways modern diets cause us to overconsume; that is, to take in more calories than we can realistically spend every day.
He argues that the are two main features of modern diets which cause this:
1.) Variety. The brain's reward system evolved under conditions of scarcity. It cannot handle the overwhelming variety of flavors and textures of food it encounters in modern environments. Because we never would have encountered such variety in the ancestral environment, our satiety systems are overwhelmed, causing us to overeat.
This is because our satiety signals are highly tied to the type of food we consume, and not just the quantity. This is driven by our senses. We may be full of one type of flavor or taste but not another. Thus our appetite does not shut down, even though we have already taken in sufficient calories. This leads to the famed "second stomach" or "desert tummy" phenomenon.
...we're bombarded with far more variety than our hunter-gatherer ancestors ever encountered. This variety sabotages our ability to judge intake by jumping from one set of reward neurons to another. Our brain shuts down the reward response for flavors it’s experiencing but leaves others exposed, a phenomenon called sensory specific satiety.
The classic example is getting dessert at a restaurant even though you were completely stuffed from the main course. The main course is usually savory, lighting up the reward neurons for fat and salt. By the time you've finished it, your hypothalamus has successfully extinguished the reward of savory food; you couldn't eat another bite. But dessert is sweet, and those reward neurons are open for business...
We've known about the waistline-destroying effects of variety for decades. At the dawn of the obesity epidemic in the late 1970s, researchers found that if you feed lab rats the standard, nutritionally balanced lab diet of chow and water, they will maintain a healthy weight indefinitely. But offer them a "cafeteria" diet of typical Western foods, with lots of tasty options, and they will inevitably overeat and get fat. Since the initial finding with rats, researchers have shown the same phenomenon in a range of species, from monkeys to elephants, and, unsurprisingly, in humans. (B: 222-223)
This tendency serves a useful evolutionary purpose. It prods omnivores like us to seek out a wide variety of different types of foods, which ensures we get the requisite supply of vitamins and minerals from our environment. It also assures that our bodies are able to store enough calories for a rainy day even when we are full by making our brains selectively favor more energy dense sources of calories. This is also exacerbated by the fact that the sugar in sweet foods stimulates a reflex that expands your stomach. Obesity researcher Giles Yeo explains the evolutionary reason behind the “dessert tummy” phenomenon:
[52:34] Let's hearken back to 50,000 years ago in the Serengeti. Imagine it's taken me 2,000 calories to take down an antelope. So when I get back to the village I have to eat at least 2,000 calories. But if I only ate 2,000 calories, there's no guarantee I'll get the antelope the next time.
So what happens is, the part of the brain which makes eating feel nice takes over so that you'll eat more than you need. The question is, how do you get past the mechanical problem of being filled with 2,000 calories worth of antelope?
Well, your brain…begins to increase the caloric density of the food that [it] wants to eat. Which means that for every given gram of food you eat, you can get more calories so that you can stuff them all into all the little nooks and crannies. So what is high in caloric density? Fifty-thousand years ago there would have been foods high in free sugars—so ripe fruit and maybe some honey. And, obviously, fat.
What is high in sugar and high in fat? Dessert. So your 'dessert tummy' is a holdover from your time in the Serengeti to make sure you could continue eating as much as possible, even when you are stuffed to the gunnels, so that you could prepare yourself for a famine that's not going to come.
Is Obesity a Choice? - with Giles Yeo (The Royal Institution)
2.) Palatability. This is a fancy term meaning foods that are deliberately designed to get us to overeat them.
While the brain has evolutionary mechanisms that prevent us from overeating, “palatable” foods are artificially engineered to manipulate our evolutionary reward pathways which are targeted to sugar, salt and fat. The food industry refers to this as the Bliss Point. Their foods are specifically designed to hit this Bliss Point using a mix of salt, fat and sugar in order to maximize deliciousness, therefore generating higher profits for the food industry. The profits accrue to them, but the consequences—including the enormous health care costs—are borne by the rest of society. That's how capitalism works, by externalizing costs.
In addition, in order to make processed foods shelf-stable, nutrients and fiber are removed. To make these foods palatable to consumers, then, they add sugar, salt, and fat back in. They also add in artificial colors, flavors, thickeners, emulsifiers, gelling agents, and so on. Such modern "junk foods" foods therefore have the distinction of being: 1.) highly palatable; 2.) calorically dense; and, 3.) not very nutritious. Therefore, we naturally tend to overeat these types of foods, because our body is taking in calories but our brain is not receiving the proper satiety signals because our body knows that it's not getting the nutrients it requires.
Additionally, these "convenience foods” are expressly designed to be prepared quickly and easily with minimal cooking time. This makes them the "go-to" foods for people in our perennially time-strapped society, especially for economically disadvantaged people who are perpetually under chronic stress (which also contributes to weight gain).
Processed foods also tend to cause spikes in insulin levels due to having the fiber stripped out of them while adding back in sugars and starches. And, to top it all off, we are constantly bombarded with messages to consume more of these types of foods by ubiquitous advertising. Supermarkets deliberately place them front and center, while placing natural, whole foods in the back as far as possible from the entrance: "Wandering the aisles of processed foods at your local supermarket with your Paleolithic food reward system and hypothalamus is like bringing a stone hand axe to a gunfight." (B: 224)
The other major problem with modern foods is that they are literally designed to be overeaten...The human brain has reward centers that respond strongly to food, particularly fat and sugar. But not all foods are created equal.
Some foods, like an unseasoned, boiled potato, hardly budge the reward system. Delicious foods—typically some combination of fat, carbs, and salt—activate our reward system like a symphony orchestra, with dopamine and other reward molecules flooding our brain and making us feel great. Researchers would describe these delicious foods as "highly palatable." In other words, we like to eat them. (B: 221)
Much of the food we buy at the supermarket, the canned and packaged foods that my Hadza friends find so amusing, have been engineered beyond anything our ancestors would have recognized. Fiber, protein, and anything that will make you feel full is removed. Sugar, fat, salt, and other things to tickle your reward system are added. As a result, added sugars and oils are two leading sources of calories in the American diet today, accounting for fully one-third of the energy we consume. Our evolved reward systems are unprepared for the intensity and breadth of reward signals that these processed foods provide. Our hypothalamus is too slow to shut down our appetite, and we overconsume. (B: 223)
These foods are often referred to as hyper-processed or ultraprocessed foods. There's a lot of confusion surrounding his term. Obviously nearly all the food we eat is processed in some way. It's simply what humans do—even chopping and cooking is a form of processing. Some foods like cassava—which is a staple in many parts of the world—are even deadly without processing.
I describe it this way: ultraprocessed foods are foods which have been stripped down to their basic chemical constituents and recombined in some way. That's something we could never accomplish in the past. Another definition might be the kinds of processing you can't do in the average kitchen using regular cooking tools and equipment—you need a laboratory in order to make them. A more formal definition can be found here: Processed Foods and Health (Harvard School of Public Health). The NOVA Food Classification System (PDF) is another resource.
Also commonly referred to as “highly processed foods,” these are foods from the prior group that go beyond the incorporation of salt, sweeteners, or fat to include artificial colors and flavors and preservatives that promote shelf stability, preserve texture, and increase palatability. Several processing steps using multiple ingredients comprise the ultra-processed food.
It is speculated that these foods are designed to specifically increase cravings so that people will overeat them and purchase more. They are typically ready-to-eat with minimal additional preparation. Not all but some of these foods tend to be low in fiber and nutrients. Examples are sugary drinks, cookies, some crackers, chips, and breakfast cereals, some frozen dinners, and luncheon meats.
Anthropologist Bill Schindler has an even better differentiation. He points out that traditional forms of food processing like cooking or fermentation make nutrients more bioavailable to us—that is, they make raw foods more nutritious. A classic example is nixtamalization, which is the addition of alkali to corn to make nutrients such as niacin biovailable to us, without which we are vulnerable to diseases like pellagra if we eat too high a proportion of it in our diet. Cooking, soaking, pounding, leaching, fermenting, and other such processes fall into this category. The purpose of food processing by the food industry, on the other hand, is to make foods that are both highly profitable, palatable, and shelf-stable. This results in foods that are actually less nutritious and filling for us than their natural counterparts. As he says, for the first time in history we’ve managed to create obesity and malnutrition in the same individual.
The average person in modern post-industrial societies today gets around half of their calories on average from these ultraprocessed foods, especially if they are unfortunate enough to reside in so-called "food deserts" (ponder that term for a minute):
Ultra-processed food consumption grew from 53.5 percent of calories in the beginning of the period studied (2001-2002) to 57 percent at the end (2017-2018). The intake of ready-to-eat or heat meals, like frozen dinners, increased the most, while the intake of some sugary foods and drinks declined. In contrast, the consumption of whole foods decreased from 32.7 percent to 27.4 percent of calories, mostly due to people eating less meat and dairy.
Americans are eating more ultra-processed foods (Science Daily)
It's Not Just Salt, Sugar, Fat: Study Finds Ultra-Processed Foods Drive Weight Gain (NPR)
Ultra-processed foods and the corporate capture of nutrition—an essay by Gyorgy Scrinis (the BMJ)
How ultra-processed food took over your shopping basket (The Guardian Long Reads)
Do we need to talk about ‘ultra-processed food’? (BBC World Service Podcast)
It's obvious that hunter-gatherers like the Hadza lack both excessive variety and highly palatable processed foods. This prevents them from overeating. The foods they encounter are not engineered in a lab, they are not shelf stable, they are not designed to hit the "bliss point," and they are not stripped of nutrients or fiber. They are the foods Mother Nature designed for us to eat over millions of years. In fact, the Hadza diet is actually quite bland and boring, as Pontzer informs us:
I've sampled a range of Hadza foods, from honey and tubers to several types of berries and meat...here's the truth: Hadza food isn't very exciting. Aside from the honey and some of the tangy fruits, it's all quite bland. Spices are unheard of, other than the occasional sparing dash of salt. Nearly all the food is served on its own, either raw, roasted, or boiled. It's not what most Westerners would describe as tasty or even appealing. No food is too bloody, too old, or too unsightly. If you've ever opened your grill the day after a big barbecue to find a cold, forgotten drumstick and a lonely potato blackened on the grate, you've encountered Hadza cuisine.
...The Hadza diet isn't low-carb, ketogenic, or vegetarian, and they don't starve or fast intermittently. Instead, like other small-scale societies, their diet is simple and filling, with plenty of tubers and berries that are high in fiber and meat with lots of protein (the Hadza eat about five times as much fiber each day as a typical American). It's relatively low in fat (although the proportions of saturated and unsaturated fats haven't been studied), which likely helps protect them against heart disease. There is always food available on the landscape (tubers are always in season), but they have to work to get it. They aren't constantly surrounded by a wide variety of delicious foods, much less processed foods engineered to be overeaten. As a result, the Hadza don't develop obesity and metabolic disease for the simple reason that their food environment doesn't drive them to overconsume. (B: 229-230)
Recommendations
Pontzer recommends that we should arrange our diet around foods that are, "filling and nutrient-rich without packing in a lot of calories." We should strive to eliminate calorie-rich, processed foods from our diet and replace them with "protein- or fiber- rich alternatives like plain nuts, fruit, or fresh veggies". "Cooking for yourself at home can help too, as "most restaurants are in the business of making delicious food that's easy to overeat." He also recommends reducing our stress levels (good luck!). (B: 227)
One point that Pontzer strangely does not make—but I will—is that we increasingly drink our calories. For basically all of human history until very recently, the only thing available for us to drink was water. Hunter-gatherers would not have had access to alcoholic beverages, and there was no milk to drink before animals were domesticated. The only other thing to drink besides water would have been tinctures or infusions such as bone broth. Therefore, we never evolved a satiety signal for beverages—unlike with solid foods—because liquids provided zero calories for the vast majority of human evolution.
That's not the case today. Have you ever looked at the amount of calories on the side of one of those Starbucks coffee beverages? There are over 230 calories in a single small bottle! That means you can easily take in 230 calories in just a few seconds and not even notice it (and believe me, I have). If you ate 230 calories of, say, bacon or cheese or potatoes—or even cake—you would receive satiety signals that you will not if those calories are delivered to your body in liquid form. That's a lot of calories, and those calories quickly add up. Plus, these beverages have tons of sugar and fat in them, stoking our bliss point.
It’s nearly impossible to find anything to drink today that's not loaded with sugar and calories except plain water, especially in the United States. You can try this experiment yourself. Seek out the cooler in any supermarket, gas station, or bodega and see how many of the literally hundreds of beverages on offer don't have 100+ calories and lots of sugar. The only ones I can find are plain bottled water and unsweetened tea, which is what I try to drink (and it's often sold out now due to shortages). And the "zero calorie" sweeteners that they put in beverages today are not a panacea—they adversely affect both insulin levels and gut microbiota: "Even non-nutritive sweeteners, which have no calories at all, can stimulate the insulin response. Sucralose in humans, for example, raises the insulin level 22 percent higher." (OC: 191). Zero-calorie sweeteners assume that excess calories are the only culprit behind weight gain, but as we'll see, this may not be the whole story.
The most filling foods, he informs us, are whole foods like fresh fruit, fish, steak, and potatoes. Less filling are processed foods like white bread, cereal, and flavored yogurt. The least filling are baked treats like cookies, cakes and croissants. The common feature appears to be the less processing, the more filling. And also, the least filling foods have the most sugar and refined carbohydrates, while the most filling foods have plenty of satiating fat, protein and fiber. Ironically, those recommendations are pretty much exactly in line with what the Paleo diet recommends.
[A] wide range of diets can be healthy. As a general rule, we ought to seek out foods higher in fiber and protein that fill us up, and avoid processed foods with added sugars and fats that push our food reward systems over the edge. The diet that works for you is the one that allows you to achieve and maintain a healthy weight without feeling like you're starving. (230)
How do some people nevertheless manage to stay slim and healthy even in our obesogenic environment? The answer seems to boil down to simply genetics. Some people have a greater resistance to becoming fat than others due to various genetic factors. We know this from twin studies, for example. Scientists have identified more than 1,000 genes that are linked to obesity, and are finding more all the time. This is something to think about for people who advocate bullying, humiliation and “fat-shaming” overweight people as a means of reducing obesity in the guise of “doing them a favor.” Not surprisingly, this method has a very poor track record of success, but it allows certain people to feel smug and superior, giving sanctimonious lectures about “personal responsibility” and engaging in victim-blaming (blaming individuals for endemic social problems is what America does best).
Although the "thrifty gene" hypothesis has gone out of favor, it seems likely to me that people whose ancestors lived in places where famine was common—like European farmers, for example—would naturally develop genetic adaptations to intermittent food scarcity. They are ones who survived and reproduced. This may not explain the whole cause of obesity, but it’s probably a contributing factor in my opinion.
Living with obesity: The people who are hard-wired to store fat (BBC)
The explanation Pontzer gives above is basically the same one offered by obesity researcher Dr. Stephen Guyenet in his book The Hungry Brain, which Pontzer cites approvingly.
Seduced by Food: Obesity and the Human Brain (Boing Boing)
But really, is any of this advice all that different than what the Paleo Diet recommended? After all, the core fundamental premise of the Paleo Diet is that we have not evolved to eat the kinds of foods we encounter in our modern environments. That's pretty much the exactly what Pontzer stated, above. He seems pretty hung up on the characterization of the Paleo Diet as being low in carbohydrates and high in protein, and whether or not that's an accurate portrayal of hunter-gatherer diets (who don't actually live in the Paleolithic). He also takes issue with the notion that there is a single specific macronutrient ratio that is somehow more natural for us to eat—something that Paleo Diet advocates explicitly do not claim.
Rather than obsessing over whether or not the Paleo Diet is historically or ethnographically accurate, why not focus on the big picture, which is the fact that there is a fundamental mismatch between the way our bodies and brains evolved as hunter-gatherers for millions of years and the artificial environments we find ourselves living in today? After all, it was that insight which led to the Paleo Diet being developed in the first place. Remember, nothing in nutrition makes sense except in light of evolution. Isn't that how we know what to feed zoo animals?
This explains why both Paleo and Weston Price approaches (and many others) succeed in practice. They remove the artificial and processed junk foods that cause us to overeat. They remove foods that we find less satiating like cookies, croissants, bagels, and pasta, and focus on calorie-dense whole foods. They cut out the simple sugars. They add in a lot of foods that take longer for us to digest and are full of protein, fat and fiber. Even high-carb foods like grains and legumes that are prepared in a traditional manner contain large amounts of fiber which causes carbohydrates to be digested more slowly and modulates the insulin response, unlike the highly refined carbohydrates that form the basis of Western-style diets. And variety is curtailed as well—eschewing foods developed since the Neolithic Revolution certainly cuts back on your food options! So, too, does eating in season.
What all hunter-gatherer diets have in common, from the Kalahari to the Amazon rain forest, from the Arctic tundra to the highlands of New Guinea, whether plant-based or high in fat and animal protein; is that they eat only foods provided by nature. Their food is always fresh. They do not have access to ultraprocessed foods, nor could they make them even if they wanted to (except by trading with outsiders). Their diets tend to be low-glycemic, even when high in carbs, and they eat plenty of vegetables. They get meat when they can. They drink mostly water. They eat intermittently—only when food is available. They eat with the seasons. They mostly avoid the three "white poisons"—sugar, salt and flour. They don’t eat excessive sugar (with a few notable exceptions) or heavily processed carbohydrates. Plus, they eat the same foods as their ancestors did going back countless thousands of years—meaning the foods that they are adapted to eat. That's a little harder for those of us whose ancestors were peasants in "civilized" societies, but the old adage, "don't eat foods your grandmother wouldn't recognize" still has value (although we may soon have to start going back a few more generations). And peasant food is quite delicious! Most of it basically revolved around pottage—putting whatever was available into a stew pot and cooking it for long periods of time.
There are a few competing theories behind the rise in obesity, however. The major one is known as the Carbohydrate Insulin Model (CIM). This theory argues that excessive consumption of high-glycemic carbohydrates in modern diets causes a disregulation of the body’s evolved systems of weight management—including the body’s Set Point. As Gary Taubes—one of the most vocal proponents of this theory— puts it, “obesity is not an energy balance disorder, but a hormonal or constitutional disorder, a dysregulation of fat storage and metabolism, a disorder of fuel-partitioning.” As we’ve seen above, Pontzer denies that carbohydrates, sugar or insulin play any role whatsoever in metabolic disease and weight gain—only calories matter. I’m not so certain. Next time, we’ll look at the Carbohydrate Insulin Model and some of the main criticisms of it.
Until I got to the end, I was wondering if you had read any Taubes. Speaking from personal experience, I think he's right that the standard "calories in- calories out" formula is just wrong. I do believe that our ultra-processed diet is certainly effecting our overall health, but I think its primary effect on weight gain is what keto proponents claim: it delivers easy carbs and sugars to people who's metabolisms, for whatever genetic reason, can't handle them in a non-disordered way. Here comes my personal anecdote (not intended to be one size-fits-all advice): my blood sugar reached diabetic levels early last spring, but I went on keto, lost just over 50 pounds, and brought my A1C levels back to normal. All while living the same sedentary lifestyle, if anything even more sedentary as the pandemic reduced the time I used to spend walking in and around the office. So, I'm skeptical of Pontzer's conclusions, at least as they might apply to a modern descendent of Northern European peoples, with whatever genetic metabolic adaptations that has gifted or cursed me with. I'm looking forward to your exploration of CIM.
Thanks for doing this series, Chad.
I do remember getting Coke in the house in high school was a treat (in the early 80s); after all, two liters cost over a buck! Now, two liters still cost over a buck, or less… but I used to make five bucks an hour, and that was decent money.
At that time, though, I remember a picture in a magazine everyone was talking about. Someone had put a Coke in a bottle away and forgotten about it for a few years. When they exhumed it, the cane sugars had re-crystallized and fell out of the solution, becoming visible and filling the bottom almost half of the bottle. "Oh, noes!" people shouted, "Sweet drinks have so much sugar!"
My neighbor (before her retirement, chief biologist at a local bottling plant) pointed out to me that high-fructose corn sweetener was chosen largely because it was liquid, and would not crystallize, causing bad press.
Thus far, the fairly recent introduction of this corn shit means that it has been studied (as far as I can determine) not so much, especially when it comes to whether it adheres to the CICO model. I do hope you've tripped across something about this. Even if you haven't, no matter.
Laters!
—Perry
aka J,yAA.