You can get fruits and fruit juices in your winter months, that is newer. OJ came in small glasses because it too was a luxury.

But HN linked an article a few years back about some research indicating that in the 1980s people ate as many or more callories, and got on average less physical activity, but were significantly less overweight. They reaction was that it was wrong, because thermodynamics, but the thermodynamic argument is a vast oversimplification. We can and do excrete plenty of energy such that other organisms post process our waste. Fat in particular can go unused with little notice. We can burn or conserve energy in ways that are hard to measure by just observing behavior. Given that complexity, it wouldn't surprise me that chronic inflammation could be a culprit. It could be the removal of a burden too, such that we are more efficient at processing calories. The food equivalent of meth amphetamine being available everywhere and cheaply doesn't help either, but enough people are studying it that I don't think it will be one simple thing.

do you have a link to the article or remember the authors

this is fantastic, thanks

10.1016/j.orcp.2015.08.007

Food is part of the equation (marketing and availabity as well as ingredients)

But then there's the rise of the car, and of screen-based jobs/lifestyles, and other little conveniences that remove any last little bits of physical effort from life, from takeaway delivery to dishwashers to power tools.

Exercise used to be an unavoidable part of life.

Modern fast food is deliberately engineered to make it as addictive as possible while still being palatable and cheap to produce, in order to maximize sales.

That sounds more nefarious than I intended, so let me rephrase it. Modern fast food is the result of rapidly iterating, debugging, and optimizing recipes in a huge market for the last 70 years, leaving only the best selling, low cost, consistently reproducible recipes and discarding the rest. This process naturally selects recipes that contain lots of junk calories and bring in the most repeat customers.

Although many of the ingredients and similar foods have been around for centuries, it wasn't possible to do this kind of agile cooking on a massive scale until after WW2.

this is clearly a thing that has happened, and it is a crucial link in the chain, but there's still a missing link.

wouldn't it be more profitable if those recipes happened to have low caloric density, like coca-cola? then you could sell each customer six meals a day instead of three, and they'd be more profitable because they'd mostly be made out of water, which is cheaper than deodorized canola oil and palm oil, much less potatoes, texturized soy protein, mechanically separated chicken, and beef. you'd maybe have to include enough cellulose and xanthan gum to make it seem solid, but that wouldn't overcome the cost savings from removing the expensive calorie-bearing ingredients. it's even legal!

yet fast-food consumers have been gravitating to the macronutrient-rich menu items, not texturized carboxymethylcellulose jello, which would undoubtedly be widely available if it sold well. so they are following their homeostatic regulatory system to seek calories

their homeostasis is just broken

what broke the homeostasis?

i don't think it's an intentional thing or even a means to improve sales. if wendy's breaks your homeostatic feedback and mcdonald's doesn't, will that help them competitively? no, because their metabolically damaged customers will still eat at mcdonald's, except for the most loyal ones. if wendy's goes out of business, it'll take a generation for mcdonald's to see the result in terms of declining sales. even then, they're unlikely to be able to recognize that the demise of wendy's is the reason for their troubles

it's plausible that it's nothing more than 'ultra-palatable food makes you overeat, which disrupts your homeostasis'. but i'm skeptical of that because people seem to be able to eat very palatable food occasionally, or even often, without disrupting it

Coca-Cola is indeed highly profitable, but American consumers have indicated time and again that they want some real bread and beef to go with that Coca-Cola. They want to feel reasonably full, and they can't come back 6 times a day no matter what, because they have to work in order to pay for your burger.

You're not going to make a large profit if you diverge too far from this social norm. Don't think like a startup, because we're talking about traditional multinational businesses here.

i don't think it's a question of social norms. if people were adhering to pre-mcdonalds social norms, they wouldn't be going somewhere besides their house (a restaurant, but one without waiters) and sitting on brightly colored plastic benches eating mechanically separated chicken glued together with modified food starch cut with texturized soy protein

people's appetite is evidently for calories, and they commonly regulate their caloric intake or metabolic rate to within 0.5% in order to maintain their level of obesity. social norms are not capable of that kind of precision

consider, if you gain only 5 kg in ten years, which many obese mcdonalds eaters in the usa do, that's a caloric excess of 5 kcal per day. half a gram of fat per day. that's 0.3% of a metabolic rate of 1666 kcal per day or 0.2% of 2500 kcal/day. if they were to eat 0.3% less calories than they were burning instead of 0.3% more, they'd be losing 5 kg every ten years, not gaining it

so the homeostatic feedback mechanism is almost working. it's clearly not completely broken. its error is well under 1%. but it does evidently have a systematic error across the population. and fast-food optimization for profit by itself is an insufficient explanation for that