[thucydides]

Let's assume this graph is correct. Why did humans 100 years ago consume fewer calories? The body is a complex system with many homeostatic mechanisms. We stop eating when we're full (generally). What has adjusted that homeostatic thermostat upward? Why did obesity increase linearly for half a century and then suddenly increase exponentially starting in 1980? Why are wild animals and laboratory animals also more obese than 100 years ago?

[jdietrich]

>Why did humans 100 years ago consume fewer calories?

Because they couldn't afford to eat more. In 1900, the average American household spent 43% of their income on food.

https://www.theatlantic.com/business/archive/2012/04/how-ame...

[inglor_cz]

"Because they couldn't afford to eat more."

But people differ in their incomes. While there always were fat rich people, if food prices were the limiting factor, your average noble from the House of Lords of 1930 would be as fat as average people are today. And yet if you look at those black and white photos of important politicians, businesspeople etc., they were way less fat than an average contemporary student.

This is the Pacific War Council in the early 1940s. Do you believe that those people, decision makers whose decisions affected lives of millions, couldn't afford to eat ad libitum?

https://en.wikipedia.org/wiki/Edward_Wood,_1st_Earl_of_Halif...

Today, they would weigh +15 kg each at least, and asking their doctors for tirzepatide.

[thucydides]

Guatemala (arbitrary choice) spent 35% of their income on food in 2016, but 66% were overweight or obese.

I don't know what's causing obesity, but it doesn't seem to be income, given everyone worldwide exploded into fatness around 1980.

And I'm not satisfied with flimsy hypotheses, such as a historically unprecedented worldwide diminution in human "willpower."

https://opendataforafrica.org/atlas/Guatemala/topics/Food-Se... https://data.worldobesity.org/country/guatemala-85/#data_tre...

[jampekka]

> As to why people eat more, it's probably due to higher energy density food, advertising (especially to children) and lost norms about eating (e.g. sugary stuff is not "proper food").

Animals, wild and lab, are probably affected by human food production.

[Izkata]

> Why did obesity increase linearly for half a century and then suddenly increase exponentially starting in 1980?

I do know one thing people used to jump on that coincides with this timing, but I don't know how likely it is to be a/the culprit - high-fructose corn syrup. It's the green line on this graph: https://en.wikipedia.org/wiki/File:US_Sweetener_consumption,...