I was struggling to think of a good way to launch this article on obesity, the phenomenon of the global obesity epidemic. Then this morning I realized I had a good way to do it, and that's to tell a funny story. About 20 years ago I was on the telephone with the spokesman of JP Morgan Chase, Adam Castellani. I have vague memories of the conversation, it was brief. I had probably been asking to interview the CEO of JP Morgan Chase. “In 2003, William B. Harrison Jr. was the Chairman and CEO of JPMorgan Chase. He held the role of Chairman and Chief Executive Officer from November 2001 until December 31, 2005.”

I don't remember much about this conversation, as I said. But I do recall that he was really puzzled and certainly amazed by his interaction with me, by World Affairs Monthly. This is what I wrote in October 2007:

“'Where do you get your ideas?' This is what Adam Castellani, the spokesman for J.P. Morgan Investment Banking, once asked me several years ago. One might ask what I thought of this question when he asked it. Well, I was more or less polite when he blurted out this question to me – and yes, it is both a stupid and bizarre question. What was I supposed to say in reply?”

Actually, I do think I told Castellani that I obviously had a high IQ – I was sort of joking. I also told him that everyone was really stupid, so it was not really difficult to be intelligent. I don't know what Castellani is doing now. So where do I get my ideas? Is it a stupid question? Again, I quote myself:

“So, if I do not steal my ideas (without credit) from my colleagues, just how do I get my ideas? Well, it should be pretty obvious that I get my ideas from a long experience with the material. I work hard, and I am meticulous in my approach to research. Once I do my research, and I have thought through the whole matter pretty thoroughly, I undertake to write about it. But I plan things out very carefully. And this all creates power, immense power and influence.”

Artificial Intelligence is a technology that will only make my job easier. "It saves you a lot of work," my son Christophe just told me yesterday. AI will not solve any problems, it will not come up with new ideas, new theories, AI does not “think” – this is just a “science fiction” fantasy.

“HAL 9000 is the sentient, artificial intelligence computer and primary antagonist in Arthur C. Clarke's Space Odyssey series, most notably in the film 2001: A Space Odyssey. HAL controls the Discovery One spacecraft and, due to conflicting programming to keep the mission's true purpose secret from the crew, develops a form of guilt and paranoia, leading it to kill the astronauts to protect itself and the mission.”

I saw the movie in 1968. I was 10 years old. My mother, Diane, drove me several miles over to the movie theater and she dropped me off. I watched the film, which was 2 hours and 21 minutes long. It was science fiction – that's right, fiction! Then she picked me up and we drove back to our home in Saratoga, California. I think I told her it was kind of stupid. I thought it was something of a joke. Arthur C. Clarke was a homosexual, he liked to have sexual relations with young boys. I knew Clarke's good friend, Eric Burgess. Burgess was not homosexual. “Clarke lived in Sri Lanka from 1956 until his death in 2008.” It is interesting that Sam Altman – OpenAI fame – is also homosexual. Is science fiction a male homosexual thing?

So where do I get my ideas? Well, the answer is perhaps unsatisfying: I undertake research for long periods of time, I analyze the information and data, and I do not make any premature judgments or conclusions. I do not rush things. I just go where it takes me, the research.

So finally I get to the purpose of this article, which is to explain the global obesity epidemic. It has been building up since the late 1970s.

“Obesity is defined as having a body mass index (BMI) greater than or equal to 30 kg/m2, and in June 2013 the American Medical Association classified it as a disease.”

"In the United States, the Centers for Disease Control and Prevention (CDC) reports that almost 20% of children and teens aged 2 to 19 are obese, with the prevalence increasing with age, from 12.7% in children 2–5 to 22.2% in adolescents 12–19 between 2017 and 2020. These statistics indicate a significant health concern, with obesity in children linked to potential long-term health issues such as heart disease and type 2 diabetes." 

It is most definitely not a disease or disorder, so the American Medical Association is wrong.

There are 4 variables which, I believe, explain the global obesity phenomenon. Here I list them, they are not in order of importance. I believe they are all equally important, however I would argue that genetics [and epigenetics] is the foundational variable.

1+ you might say that this is the human mammal's “famine insurance” and that this insurance is taken out by calling on the genome. It is epigenetic, meaning that if 50 years go by and there are no famines – where huge numbers die of starvation – then the genetic material would adjust for that new development and the need to “take out famine insurance” would diminish, if not go away entirely. You fill up your tank, you might say. Fat is stored, for a rainy day, to use a silly expression. And it is not just a little fat, it is a major fat storage operation. Maybe 30% of your body weight would be in fat. Then there are the “overweight” human mammals. They are less fat, but they are still fat. I would argue that these overweight human mammals come from the lower socioeconomic levels of society. They were peasants and workers, low status individuals. Their insurance had to be there, otherwise they would likely die in a famine. And famines were relatively common, in history. Not until after 1945 did famines begin to diminish in number and intensity. And Paul Ehrlich noted that there were still famines in India in the 1960s. So he wrote his book on the population bomb.

“The Population Bomb is a 1968 book co-authored by former Stanford University professor Paul R. Ehrlich and former Stanford senior researcher in conservation biology Anne H. Ehrlich. From the opening page, it predicted worldwide famines due to overpopulation, as well as other major societal upheavals, and advocated immediate action to limit population growth.”

I know Ehrlich, I have interviewed him, March 2011. World Affairs Monthly. I will republish the interview with him as soon as possible.

If your ancestors were high in the socioeconomic scale, then it is likely you will not be overweight or obese. You might just be a little overweight – not skinny. High income families in the United States and Europe are rarely obese or overweight.

In fact, the obesity epidemic is going to follow the 80/20 Rule. 80% of the human mammals are going to be overweight or obese – globally. And 20% will not be overweight or obese. The 20% will be what you might call the elite, or the ones at the top of the socioeconomic scale. Eventually it will be 80/20. That's what I predict. I also predict that among the 80% there will be some 60% obese and 40% overweight. This is my estimate.  

2+ the second variable is what my friend Robert H. Lustig MD [neuroendocrinologist at University of California, San Francisco, professor emeritus of pediatrics] identified. According to him, this is what's going on in the human body, and I am confident he is right. I did an interview with Lustig on Sep 12, 2024. Published at bottleneckanimal.com. If I remember correctly, I think he said that a high carbohydrate and sugar intake is the norm in the Western world, in the United States in particular. He told me that 75% of the food in your typical American supermarket is processed food. What happens is that this sugar [carbohydrate] raises the insulin levels in the blood. He told me that insulin levels are about double the level they were in 1980. These high insulin levels in the blood act to disable the hormone leptin, and leptin is what acts in the brain to shut down appetite.

“Leptin is a protein hormone produced by fat cells (adipocytes) that regulates long-term energy balance by signaling satiety (fullness) to the brain, thereby controlling food intake and energy expenditure. It acts by binding to leptin receptors in the hypothalamus, which suppresses appetite and increases energy use. While leptin is crucial for weight management, most obese individuals have high leptin levels but are resistant to its effects, making exogenous leptin ineffective for weight loss in these cases.”

So you can reduce your carbohydrate intake and you can reduce your consumption of processed foods and other “garbage food” that is commonly very cheap and plentiful in the Western world and increasingly all over the world. Yet the urge will still be there – famine insurance. A full tank -- and often fill it up -- keep it full all the time. Just in case. I am having fun with this metaphor. You can also increase your calorie expenditure, by exercising. You can try, but you will still be hungry, even hungrier. But calorie expenditure will likely ultimately result in weight loss, but it will have to be a lot of energy expended.

3+ the third variable is the cost of food as a ratio of income. 100 years ago the cost of food in the Western world was probably around 30% of your income. That's my estimate, it could have been a little higher. Hundreds of years ago the ratio was certainly higher, probably close to 50% or even higher. Since 1945 the cost of food has plummeted, and of course this has been a global phenomenon. Today in the Western world the ratio is now probably an average of 7-10%. This ratio can vary a lot, obviously. But the most likely scenario is a pretty low ratio. And so the human mammal – all over the world – can eat a lot and get fat. And so the human mammal gets into a position where “fear of doing without food” is banished, for a while. Yes, that's “famine insurance.”

4+ [September 2, 2025: This morning I wake up and I see a text message from a friend of mine, we've known each other for 20 years. He's a general surgeon in Denver, Colorado. We've been discussing “medical science” pretty much nonstop, since we've become acquainted. His text message: “Agree. It's all about the food, with all its added sugar in various forms. This is obvious. And you forgot to add sleep function....All your medical theories are spot on....The more I understand medicine the more I don't. All medical doctors are now learning stuff you would agree with.”

I had sent him a link to this article on obesity. It's amazing – even I can make mistakes! Hilarious. I had totally forgotten to include the 4th, which is the sleep function. I think I know why (actually, it could be because I had lymphoma and my brain is still not working at a high level) I initially failed to add sleep, and that's because I am not certain how much the sleep function is in deficit, in the United States, and all over the world. But since the United States has one of the highest rates of obesity – if not the highest – in the Western world, then we can safely assume that the sleep function is the 4th variable. “Capitalism” in the United States means a very tough and indeed demanding environment for the lower rungs of the socioeconomic scale. Sleep deprivation is inevitably going to be an issue. Sleep deficits are now common, compared to 50 years ago.

"Based on decades of sleep research, Americans now sleep significantly less than they did 50 years ago, with studies reporting a decline of over an hour per night."

It is now known and well understood that deficits in the sleep function will cause a decrease of the hormone leptin in the blood, thus disabling the function in the brain which signals that you are full or had enough to eat.

“Yes, loss of sleep increases hunger by disrupting appetite-regulating hormones, specifically by decreasing the 'fullness' hormone leptin and increasing the 'hunger' hormone ghrelin. It also elevates levels of 2-AG, a chemical that amplifies the joy of eating, particularly high-fat, sweet, and salty foods, leading to increased cravings and potentially overeating.”

It's interesting and indeed fascinating that I forgot the 4th, the sleep function. Again, I can make mistakes. Hilarious. That's what we need AI for – but AI did not tell me! AI is not intelligent. AI is not a scientist! AI is just a tool, and while it is certainly a powerful too, its limitations are subject to the limitations of the researcher. Hilarious. Anyway, I have added the 4th variable. So, "peer review" does inded have some merit, maybe not much, but it has admittedly helped me here.]

And how much confidence do I have that this theory is generally correct? I would say that I have very high confidence that this is correct. The MAHA movement [Make America Healthy Again] in the United States is certainly good, and I am impressed that people want to be healthy and live long lives. But I do not think the prevalence of obesity is going away anytime soon. On the contrary, I predict it will increase, until the 80/20 ratio is established.

Of course, there are now the weight loss "medications." If the 80% take these drugs, then perhaps yes there will be far less obesity. But we will have to assume the side effects are tolerable and risks low when taking these drugs for weight loss. I tend to think there will be side effects, and that these side effects will be concerning, but I am not well-informed on this issue. I will look into it, but I tend to think, at the moment, that obesity will be an ever-present phenomenon plaguing the human mammal for decades to come. At some point, the "epigenetic system" will kick in, however. And that's when the fatties will disappear. We will all be good, then.

A final note: as a consequence of there being so many obese human mammals, the health of the majority of the population will be adversely affected. The 80% will be afflicted with atherosclerosis, diabetes, and all manner of disorders in the body. We see this happening already. The [famine] insurance policy is costly, that's obvious. I have argued that cancer and aging are closely related, I will be publishing soon an article on cancer and aging. The 80% are going to be living shorter lives, that's for sure. At the moment, I do not think there is much to do about it. We must improve the quality of food. And we must "get the word out" as to the nature of the problem.