Is the obesity epidemic a mystery? Part 2

So in Part 1, I looked at the claim by Slim Mold Time Mold that the obesity epidemic was a mystery, and that the only factor that could account for it was chemical contamination of groundwater.

In this post, I’m going to look at some other possible explanations for the global obesity epidemic.

Highly Palatable Processed Foods

Regular readers will know that I am not anti-technology and do not subscribe to the appeal to nature fallacy.

Processing food is not an inherently bad thing. All humans eat processed food. Even hunter-gatherers.

Cooking, grinding, soaking, and fermenting are used by all populations on earth. There is not, and never has been a group of humans that lived solely on raw, unprocessed food.

There is pretty compelling evidence that it was learning to process food that enabled our pre-human ancestors to evolve larger brains and become human. By increasing the digestibility and bioavailability of calories and nutrients, our species was able to devote less time and resources to chewing and digesting food, and use it instead for cognitive ruminations.

Why is it then that modern food processing techniques seem to be leading to larger bellies rather than larger brains?

One possible reason could lie in the motivations behind the processing.

Billions of dollars, pounds and euros have been spent by food companies on R&D in order to try and sell more food. Teams of scientists have been working for decades refining techniques and recipes to produce food that we just can’t get enough of.

Lots of money plus top scientists achieved the Manhattan project, the moon landing and multiple covid19 vaccines in record time. Should it be a great surprise that they can also get people to consume more food?

I have a more detailed post on what makes modern processed foods so rewarding here, and for a really in-depth look I’d recommend Stephan Guyanet’s book The Hungry Brain. To briefly summarise, however, scientists have identified 10 factors that contribute to a food’s palatability:

• Energy Density
• Fat
• Sugar
• Starch
• Salt
• Free Glutamate (meaty flavour, i.e. MSG)
• Absence of Bitterness
• Mouthfeel (i.e. crunchy, chewy, etc)
• Smell
• Uniformity/Consistency of production

Careful manipulation of the first 9 factors produce foods that really light up all our pleasure sensors. Uniformity/Consistency of production means that each time you eat a twinkie, the experience is exactly the same, reinforcing the reward pathways in your brain.

Because of this deeply ingrained reward pathway, when you’re bored or stressed there arises a desire to eat a twinkie in order to trigger that sensation of pleasure and reward for some temporary mental alleviation. This happens regardless of whether you are actually hungry or not.

This doesn’t happen with “normally” palatable foods. No one gets stressed and reaches for the raw kale. Foods that don’t tick all the boxes will satisfy you and be really enjoyable if you’re actually hungry, but do nothing for you if it’s some other itch you’re trying to scratch.

It’s not as simple as whole food vs processed either. No one binges on pure sugar or guzzles vegetable oil from the bottle, even though they’re as processed and refined as you can get. To really press your buttons it has to combine all of the factors. That’s why you’ll typically find salt in sweet foods and sugar in savoury dishes if you read the ingredients label.

This wasn’t some evil plan intended to make everyone fat, rather it was just Moloch in action. Food companies wanted to sell more of their products. There was probably an expectation that it would be a zero-sum game – the winners would get more market share at the expense of the losers. Turns out this wasn’t the case and we’ve ended up eating more of everything! Win-win for the food giants, not so much for humanity.

Oh, and not so great for your pets either. The same techniques have been applied to Felix and Fido’s food too with the same results.

Problems: There are some niggling questions regarding this theory.

On the individual level, highly palatable processed foods are certainly a driver of obesity.

People gain weight when they overeat calories. People overeat calories when they eat highly palatable processed foods even though they’re not hungry.

Pizzas, fried potatoes, pastries, cakes, ice cream, chocolate, cookies are the types of foods that drive obesity. No one raids the fridge at midnight for broccoli and sardines.

Whether it’s paleo, vegan, Atkins, keto or low fat, all diets work by restricting or eliminating these foods.

All of these diets tend to ultimately fail because you’re not allowed to eat pizzas, fried potatoes, pastries, cakes, ice cream, chocolate, cookies, and people like eating pizzas, fried potatoes, pastries, cakes, ice cream, chocolate, cookies.

But pizzas, fried potatoes, pastries, cakes, ice cream, chocolate, cookies are nothing new.

One possible explanation is that all these billions of R&D have resulted in modern versions that are more irresistible than ever, but I’m not convinced by this.

Perhaps I’m just a food snob, but in my opinion, if you compare the modern, mass-produced supermarket versions of pizzas, fried potatoes, pastries, cakes, ice cream, chocolate, cookies to their traditional counterparts, they are poor imitations.

When I do have a treat I’m going to go for homemade Italian gelato not Ben & Jerry’s, or real butter French croissants, not some hydrogenated supermarket fake.

If the traditional versions are every bit, if not more delicious and rewarding as the new ones, and they’ve been around for hundreds of years, can highly palatable processed foods really explain rising rates of obesity?

Sugar-Sweetened Beverages

Soft drinks and sugar-laden coffees and milkshakes provide large amounts of empty calories with little to no satiating effect.

Sugar-sweetened beverages (SSBs) or sugary drinks are leading sources of added sugars in the American diet. Frequently drinking sugar-sweetened beverages is associated with weight gain/obesity, type 2 diabetes, heart disease, kidney diseases, non-alcoholic liver disease, tooth decay and cavities, and gout, a type of arthritis.1-4 Limiting the amount of SSB intake can help individuals maintain a healthy weight and have a healthy diet.

https://www.cdc.gov/nutrition/data-statistics/sugar-sweetened-beverages-intake.html

As with highly palatable processed foods, consumption of SSBs certainly explain obesity on an individual level, and cutting out SSBs is a highly effective strategy for weight loss.

Problems: Again, as with highly palatable processed foods the puzzling question is what drove the increased consumption? Coca-cola was invented in 1896, what took it so long to catch on?

(NB Before anyone can say “Good Calories, Bad Calories” please read this thorough debunking of the Carbohydrate-Insulin Model)

Cheap & Easy

Throughout most of human history, calories have been costly. Either in terms of money and/or in terms of the time and labour required to produce, gather, and prepare food. Hunger and starvation were much more common than obesity.

Modern food processing techniques, combined with industrial farming, transportation, storage and processing changed all this, making calories plentiful, cheap and easily accessible.

I noted in part i that obesity is not a modern disease, it’s been around for millennia. Previously, however, it was a disease of the rich and powerful. Kings, noblemen, the bourgoisie. Henry VIII is one such famous example:

Henry’s earlier set of armour indicates a weight of around 82 to 91 kilograms (180 to 200 pounds), with a waist measurement of 86 to 91 centimetres (34 to 36 inches). But his very last set of armour showed a waist measurement of a massive 147 to 152 centimetres (58 to 60 inches), meaning the infamous king would have weighed approximately 136 to 145 kilograms (300 to 320 pounds).

History Answers

Now it’s possible of course that Henry had some kind of genetic condition, or there was some environmental contaminant that drove his fat gain. But as he was normal weight when he was younger, and pollution wasn’t such an issue in the 16th Century, both are unlikely. There are numerous historical examples of Kings, Emperors, Sultans, or rich and powerful individuals being fat, so it seems that there’s a trend. Why might this be?

Because money and effort were no object.

Henry could afford all the food he desired and had servants to prepare and serve it for him.

We can still see these patterns in the developing world. Check out this graph of childhood obesity in India:

Note that there is a zero rate of obesity in the lower class. I don’t think that anyone is going to argue that this could be because there’s zero environmental contamination in the poorest areas of India.

In the rich modern western world, we can all eat like a king. Calories are cheap, abundant, and available at close to zero effort.

It’s not that in the past, only kings and rich folk were greedy with poor self-control, and that over time more and more of the population lost their moral fibre and willpower, rather the constraints that prevented us from overeating were removed.

Even if I had no conscious craving for cookies, if someone were to put a plate of them in front of me, I would no doubt end up eating them. Maybe I’d resist them for a while, but eventually, I’d cave.

On the flip side, sometimes I do get cravings for cookies, but if I have to go to the shop, buy the ingredients, come home, then bake the cookies, I’m probably not going to eat cookies.

Even if I was really desperate to eat cookies, if the ingredients cost £50 and the process of gathering and preparing the ingredients took several hours, I definitely wouldn’t be eating cookies.

Marketing

Engineering foods to be more palatable and rewarding aren’t the only tools available to the food companies to increase their sales.

Food, beverage and restaurant companies spend almost $14 billion per year on advertising in the United States^[1]. More than 80% of this advertising promotes fast food, sugary drinks, candy, and unhealthy snacks, dwarfing the entire $1 billion budget for all chronic disease prevention and health promotion at the U.S. Centers for Disease Control and Prevention

https://uconnruddcenter.org/research/food-marketing/

The food companies can’t literally come and place a plate of cookies in front of you, but perhaps getting an image of them in front of your eyes is the next best thing.

It’s not just advertising either. Product placement, packaging, branding, rituals… Not satanic rituals in Bohemian Grove but rituals like the twist lick dunk of an Oreo.

Problems: There is actually a debate as to whether advertising actually works or not (At least traditional forms such as TV and newspaper ads).

Whether the budgets are justified and actually result in increased profits is surprisingly unclear. That ads, and media in general, can create desires that we might not otherwise have however seems very plausible.

Anecdotal, but when watching the series Madmen, I drank considerably more whiskey than normal. Under normal circumstances I drink whiskey only very occasionally, I more or less forget that it’s there most of the time. Seeing Don and Roger enjoy a tipple however would suddenly ignite the desire in me to do the same.

Culture

People used to know how to cook. Families would eat meals together around the dining room table. Eating out was an occasional treat, as were snacks and treats.

In the 60s people might have been smoking at their desks, but they weren’t constantly grazing on snacks and high-calorie drinks.

Also, portion sizes have become much larger over time.

If you went back in time and served someone from the 60s a modern fast food restaurant meal, they’d probably be horrified. Or maybe overjoyed? In any case, they’d be shocked and probably think it was meant for two to share.

How much these changes in culture have been driven by the marketing efforts of the food companies, compared to how much the products and services of the food companies have been shaped by our desires is an interesting question.

Given the choice between the two meals above, most people are going to pick the restaurant that offers the larger meal. Thus fast-food chains have entered into some kind of bizarre arms race, where meals just keep getting bigger and bigger.

(You may ask, “why didn’t they keep the portion sizes the same but compete on price?” This is again due to the reduced cost of calories. When you buy a meal in a restaurant, most of the cost comes from the rent, utilities and labour, the actual ingredients are a tiny fraction.)

Reduced disincentives

Being obese in the 21st Century sucks much less than ever before in history, both from a psychological and physiological perspective.

Psychological: It is much more socially acceptable to be overweight or obese. If everyone around you is overweight, there’s less social pressure to stay slim. It’s also easier to avoid taking personal responsibility.

In the 80s, it really sucked to be the fat kid in school. You would be bullied relentlessly. Things didn’t get much better as an adult. If you were fat it was because you were lazy and greedy.

Bullying and fat-shaming are still a problem, but you’re no longer alone. Being obese is not your fault, you were born into an obesogenic environment, there’s no known cause or cure, diets don’t work. You’re the victim here. And being a victim is also more socially acceptable!

Physiological: When you’re overweight or obese, all forms of physical activity become extremely arduous. In part i I posted this image which shows the correlation between obesity and commuting by car.

The simplistic explanation is that commuting to work causes obesity as you burn fewer calories in the car than you would cycling or walking to work, which in turn leads to excess calories being stored as fat. This theory has been largely debunked, however, as the body regulates energy intake in response to need via hunger. If you exercise more, you’ll get hungrier and eat more calories to compensate and vice versa.

Most experts agree that if there is a causal link, it most likely runs the other way. Being obese causes you to take the car, as walking to work carrying an additional 50kg sucks.

Is this still oversimplifying things though? What if driving to work wasn’t an option? What would happen then?

While cars, escalators, lifts, mobility scooters and all the other labour saving devices may not cause obesity, might they on some level enable it?

Better Medical Care

We are getting much better at managing the diseases caused by chronic overeating.

Obesity is just one of numerous possible symptoms that years of excess calorie consumption can result in.

Diabetes, Heart Disease and Cancer have been the leading causes of death since the 1960s. But in the 1960s people were dropping like flies.

Environmental Contaminants

Some studies have found correlations found between environmental contamination such as air pollution and microplastics and obesity, others have failed: Systematic Review of Effects of Environmental Contaminants on Obesity.

It’s not impossible, and there are some vaguely plausible mechanisms.

A few things make me doubt this hypothesis, however:

• Inconsistent results – Sometimes pollution is correlated, others no
• High risk of confounders
• People (and pets) can and do lose weight through change of diet
• Distribution of obesity in the developing world
• Absence of obesity in indigenous tribes

By the latter, I’m referring to the fact that (as per the graph of Indian school children above) in the developing world, obesity is more prevalent in the richer classes than the poor. It seems very unlikely that the richest receive the most exposure, the poorest the least.

SMTM notes that indigenous tribes that follow a wide variety of traditional diets are free from obesity. A recent study by Helsinky & McGill Universities found that Indigenous Peoples around the globe are disproportionately affected by pollution.

This is not to say that environmental pollution isn’t a problem or that we shouldn’t do anything about it. Air pollution alone is thought to be responsible for over 4 million deaths per year globally. From the aforementioned study on indigenous people:

There are mounting cases worldwide in Indigenous Peoples, of a range of ill health outcomes that are linked to pollution, such as certain cancers, respiratory diseases, high rates of miscarriage, kidney diseases, etc.

McGill & Helsinki University

Pollution is definitely making us sick, killing people, and destroying the environment. It’s just probably not making us fat.

Chemicals in Processed Foods

In addition to environmental contaminants, SMTM believes that chemicals in processed foods are driving the obesity epidemic.

There have been fears about chemicals such as BPAs, phthalates, herbicides and pesticides in our food for many years now, and people have been searching very very hard for links between obesity and other illnesses.

In the article they link to a paper that makes a good summary of the current research:

What Are We Putting in Our Food That Is Making Us Fat? Food Additives, Contaminants, and Other Putative Contributors to Obesity – Amber L. Simmons et al.

The word “putative” is an interesting choice. Speculative would have been more appropriate, as any actual evidence is still lacking.

SMTM writes:

Despite this interest, all the claims have been quite mild, identifying environmental contaminants as possibly being one of many factors contributing in some small way to the obesity epidemic. In contrast, we propose that the obesity epidemic is entirely driven by environmental contaminants. The entire difference in obesity between 1980 and today is attributable to one or more contaminants that we are exposed to in our food, water, and living spaces.

(Their emphasis)

The claims are mild because most scientists are reluctant to make bold claims when they don’t have any evidence to support it, particularly when, as we’ve seen, there are many other factors that could well be contributing to the obesity epidemic in very large and meaningful ways.

They then go on to list their damning evidence:

The difference in obesity rates between countries, as well as the differences between states or provinces within a country, is also the result of differences in contamination. Some of it will be genetic, but some of it is because some places are more contaminated than others.

Or it could be differences in wealth, education, politics and culture. We often hear of the “French Paradox”. Why is it the French aren’t as fat as the British or Americans, even though they love cheese and croissants?

My guess is that anyone who is puzzled by this supposed paradox has never spent time in France. The French still know how to cook, they sit down and eat meals of real food together, they drink espressos not buckets of sugary warm milk, they eat human-sized portions. These habits are starting to change, and obesity rates are rising, but there are still enough good habits left to account for the differences.

Some of the strongest evidence for this comes from immigration. When they arrive in a new country, immigrants usually have lower obesity rates than their native counterparts do, but over time they become about as obese as the natives are. Looking at the trends, it appears that much of the effect of the contaminants occurs in the first year of exposure, though it takes 10-15 years before immigrants have obesity rates similar to the rates in the host country.

Or because they increase their personal wealth and can afford to adopt the local diet of highly palatable processed foods.

During the Cuban economic crisis known as the “Special Period”, obesity rates plummeted, from 14% obese to 7% obese.

SMTM attributes this change to a reduction in the consumption of chemicals in imported foods. But other explanations could simply be that they no longer had access to highly palatable processed foods, nor had the money to afford excess calories. The main sources of calories were white rice and sugar. Not healthy foods, but nor are they highly palatable.

One surprising fact is that the most obese countries in the world by BMI are all tiny island nations in the south or central Pacific — Nauru, Tonga, Samoa, Tuvalu, Palau, the Cook Islands, and others… To begin with, there are some reasons to suspect that this is largely an artefact. These islands all have very small populations and are genetically homogeneous, so it’s possible that much of the difference is genetic… In addition, Polynesian countries import most of their food and eat a lot of highly processed, canned meat (famously spam), which may be more contaminated than average.

There are countless cases of indigenous tribes that had perfect health and bodyweight until western foods were introduced, at which point they rapidly became obese at much higher rates than industrialised societies. The latter as we have had 50-100+ years to adapt to processed foods physically and culturally.

This is simply more evidence that it is highly palatable processed foods that are driving obesity rather than environmental contaminants. If the latter were the case, we’d see trends of obesity rising with increased environmental contamination in the absence of a change of diet. But this has (to my knowledge) never been the case. As SMTM notes, there have been no cases of obesity found in tribes eating traditional diets that are free from processed foods despite there being higher rates of environmental contamination.

The main point of agreement between myself and SMTM is that Highly Palatable Processed Foods are a major factor in the obesity epidemic.

This does of course still leave room for the possibility that it is the chemicals in the processed foods which are driving obesity. It could be that these chemicals have an effect on appetite regulation, or it could be that it is the chemicals that increase the palatability of the food.

I’m not sympathetic to these ideas though because:

• People have been getting fat eating highly palatable processed foods for 100s, if not 1000s of years, long before the discovery and inclusion of any of these chemicals in food.
• Anecdotally, I gain a few kg each time I stay at my mum’s house through eating the highly palatable home baked goods she makes. She cooks everyting from scratch usually with organic ingredients, and to my knowlege doesn’t add any BPAs or phalates.

As with environmental contaminants, I’m not saying that we shouldn’t be concerned about possible negative health effects from ingesting all of these chemicals with unknown effects. They are classed as GRAS – Generally Recognised As Safe, but this doesn’t mean they’ve been proven to be safe, just that there’s no evidence of harm as yet. Innocent until proven guilty.

All that said, in a way, I do think that these chemicals are a factor, as they are used as part of the industrial processes that help make the foods so cheap and accessible. Perhaps banning the use of these chemicals could indirectly have an effect by increasing the cost of highly palatable processed foods?

Conclusion

On the individual level, obesity is no mystery.

People gain weight when they consistently overconsume calories by eating highly palatable processed foods and drinking sugary drinks absent of true hunger. (Well, the lucky ones do).

The solution to this problem is to restrict calories to create an energy deficit until a healthy weight is achieved, then keep calories at maintenance levels to avoid regaining the weight. Any diet will do, as they all really work by the same mechanism – eliminating or restricting the consumption of highly palatable processed foods and sugary drinks.

While the solution may be simple, it is far from easy. The body resists change. The longer someone has been at a higher body weight, the harder it will fight to keep those extra fat stores – ramping up appetite, reducing metabolism, reducing the desire to move and expend calories. But with patience and perseverance, it can be done.

But pizzas, fried potatoes, pastries, cakes, ice cream, chocolate, cookies and the like have been making people fat for centuries. The mystery is why so many more people today struggle with weight control than they did just 50 years ago, what’s changed?

Though it’s not impossible that some kind of environmental contaminant in the air, water or food is playing havoc with our appetite regulation, I have yet to see any compelling evidence.

It also doesn’t explain why cutting out highly palatable processed foods and sugary drinks and instead eating a diet of whole foods enables people to control their weight simply by eating to satiety without counting calories.

I personally think that the more likely answer to the mystery is that it is economic and cultural changes that have made eating large quantities of processed foods and drinks cheap, easy, more accessible and more acceptable to more people than ever before.

Over the same time span, we have seen a massive reduction in the rates of smoking. Why is this? Is it due to a mystery chemical in the environment? Changes to the cigarettes? People magically found the willpower to quit en masse? No, it was economic and cultural changes, but this time in the opposite direction.

Cigarettes are more expensive, harder to buy, advertising has been banned, where you can smoke is restricted, there have been huge educational campaigns, and smokers have become social pariahs.

Whether we’ll be able to achieve similar results in reversing the obesity trend remains to be seen. Getting people to eat fewer highly palatable processed foods is the answer, but how we go about this when people clearly don’t want to stop eating highly palatable processed foods is going to be difficult!