Hacker News Reader

Comment by andrewmcwatters | Hacker News Reader

Is obesity really that much of a puzzle? Have you ever looked back in US history and taken a look at portion sizes through the decades? Not year-by-year, I mean across decades and decades, average portion sizes are staggeringly different.

The meals we collectively eat are different.

Remember peak "Super Size Me"? By the time that movie had come out, portion sizes from McDonalds had already shrunk significantly. Then they removed the size option, but that wasn't the height of fast food consumption at all. It occurred at least two to three decades prior.

View on HN

Were people eating smaller portion sizes just perpetually in a higher state of felt hunger than we are today? Or were people eating an amount that satiated them, and people are doing the same today, but those are different amounts of food/calories/nutrients for some reason?

IMO it's absurd how little attention the felt sensation of hunger gets in the conversation about diet. It is the thing that motivates people to eat or to avoid eating. If you take that framing, then it's especially clear what has been happening: food manufacturers have gotten really good at jamming enormous amounts of calories into extremely lightweight (as in actual weight) food. The physical weight of your food intake is a big signal for satiation. If you take this "caloric density" perspective and then go walk around the grocery store, you will be utterly shocked at how huge the caloric density gap between a Snickers bar and a watermelon is.

If we did actually need to be mobile while consuming tons of calories, Snickers (and most other manufactured foods) would be bona fide miracles.

I believe arctic explorers rely on butter for a dense calorie source. Fat has 9 calories per gram and I don't think it's possible to do better than that.

I don't think the sensation of hunger is actually ignored; it's pretty clear that drugs like ozempic were made specifically to artificially induce satiety.

Ozempic, a pharmaceutical brought to market in 2023, is not a counterpoint to "directly managing the sensation of hunger has been largely ignored in the conversation around diet."

You are begging the question, though? Yes, we clearly consume more. As simplistic as the in/out hypothesis is, that part is not really up for debate. The question is why do we consume more.

It is conceivable that it is just the availability, of course. Plenty of pet owners have found that some pets will eat as long as food is available, while some others will not. Trying to understand that seems like a good target.

Some constant in the neural net.

> The question is why do we consume more.

Because we are offered more.

Survival instinct is to eat everything in front of you. Reduce portion sizes across the board, and people would likely eat less.

That is countered by the rest of my post, though? Having had some pets that I can leave open buckets of food out for them, and they don't gain weight, something else is clearly at play.

I'm open to the idea that, statistically, more people will eat more when given more. I'm... less open to the idea that we can't learn from looking at those that don't eat in excess in those situations.

> pets

I mean, people are not pets.

I've seen plenty of pets become obese when food is unlimited. You're probably affecting the "experiment" without realizing it.

You are just repeating my first post, though? I have seen plenty of pets that do both. I've had both at the same time. Kind of obnoxious when you have one animal that you have to feed separate from others, otherwise it doesn't get any food. Super convenient when that is your only animal, as you can just make sure the bucket is there with food.

The question is literally if we can find a difference between the two animals we are talking about. And that difference may be something that is addressable not at the animal level, but at the food supply level. Maybe not, of course. But a perfectly fine question to consider.

>Survival instinct is to eat everything in front of you. Reduce portion sizes across the board, and people would likely eat less.

This is too simplistic and is not true for many people. There are also many people out there who, when faced with smaller portions, will order multiple servings or snack constantly between meals because they are always feeling the urge to eat (while typically having low energy with which to exercise).

Added sugar in so many processed foods should not be ignored, as per the findings of this study. Lower energy expenditure via ATP, blocking of ability to use stored fat for ATP, and leptin resistance blocking the satiety signal play a huge role in obesity. These all appear to be directly triggered by fructose (which is present in most sugars, not just HFCS).

Stephan Guyenet has written at length on the topic and it makes sense to me: the “why” is multifaceted, due to things like availability, palatability, etc. And these changes - like adding sugar - are probably due to marketplace evolution and forces that shape food production.

I am very open to the idea that it is multifaceted. I actually struggle to see how it could be any single thing. And I say this as someone that is convinced society consumed a lot of terrible things for a while. (Looking at you, trans fats...)

Of course it is a puzzle because if the answer were simple it would be common knowledge and no one would be obese.

Portion sizes shouldn't matter because the eater's metabolism should kick in at "full" and larger portion sizes should mean more food waste or leftovers.

Portion sizes grew but also "healthy eating" pushed things overall "healthier". The McDonalds my parents experienced as kids used more "high calorie" lards and beef fats on things like the fries, whereas today things use more "low calorie" vegetable oils. Among other changes.

There's no "smoking gun" for why obesity is such a crisis. Current generations are overall eating much "healthier" than past generations under many current metrics (whether or not you agree that food Calories are a terrible metric) and ideas of "healthier eating" but fighting more obesity. It is counter-intuitive, an incredibly complex puzzle, and either what we think of "healthier eating" is extremely wrong and/or something has broken people's metabolisms in ways we don't currently know how to fix.

But part of the question genuinely is, "were those animal fats less healthy than the high-trans-fat alternatives they were replaced with?"

Our collective understanding of what various kinds of dietary fats do to our bodies has changed several times over the last several decades, and some people have simply refused to update their understanding, while others have a financial motivation to ignore certain updates.

I have found it extremely difficult to convince parents in their late 70s, and/or small town restaurants to stop purchasing margarine with partially hydrogenated oils.

Similar with whole milk versus 2%.

and same with, "no, we don't need bread or white rice with this meal"

I do think we are finally seeing some good macronutrient research on things like animal fats versus trans-fats. It's definitely slow.

I think a factor in updating our collective understanding that is both tied to "people simply refuse" and "financial motivation" is that we have outdated metrics that desperately need a shakeup and there are too many vested interests in them and too many decades of momentum.

The hydrogenated (high-trans-fat) margarine has fewer calories than full fat butter. Numbers are "easy" and people follow the metrics you give them. Food calories are a metric of heat particles (Phlogiston) that burn away when you incinerate food in a furnace. It's obviously biased against many understandings of macronutrients: we used to make candles directly from animal fats, we all know how easily they burn, high calories shouldn't be surprising. The fact that trans-fats take much more effort to burn may be a sign that we should trust them less, because fats probably should burn easily.

If a metric is giving us funny biased-looking results, maybe we should reevaluate the metric? A lot of diets are based on calorie counting and several of those diets are run by big for-profit companies. If their systems actually worked they likely wouldn't remain profitable, would they?

>"high calorie" lards and beef fats on things like the fries, whereas today things use more "low calorie" vegetable oils.

This is nonsense. All fat is high calorie at roughly the same rate, 9 calories per gram (unless there are other additives, like we find in butter and margarine). There might be a few percentage points difference in calorie per unit mass from fat to fat but this is negligible when you're talking about a class of foods that all contain around 100 calories per tablespoon.

If you read the paper the linked article is based on, found here [0], fructose indeed appears to be the smoking gun that connects several different partially correct, but fragmented explanations for the prevalence of obesity in modern society.

[0] - https://royalsocietypublishing.org/doi/10.1098/rstb.2022.023...

Edit - you also state below that hydrogenated soybean oil (margarine) has fewer calories than butter. A quick web search disagrees, putting hydrogenated soybean oil at 884 calories per 100 grams, margarine at 719 calories per 100 grams, and butter at 717 calories per 100 grams. I'm sure it all depends on the brand and processing techniques, but overall the concept of low calorie fat is hugely misleading. Otherwise we can compare butter to ghee and determine that butter is a low calorie fat, which is more nonsense.

I find it hard to call that paper a smoking gun. It makes a great case and offers testable hypotheses but does not indicate that those hypotheses have been tested yet.

It was also just one of 16 very different theories submitted to the same meeting: https://royalsocietypublishing.org/toc/rstb/2023/378/1885

What I skimmed of the other 15 all had similarly great cases, despite very different thinking, and similarly untested hypotheses.

I don't think there is a single easy answer here. Certainly there are a lot of offered "easy" answers, among the 16 above, and all the more you see in threads around here. Again, this seems too complex a puzzle in general and the more pieces we find the more questions we have and hypotheses to test. (Whether or not you agree with my skepticism of calories and belief that they are an outdated and uselessly unscientific metric.)

It's more complicated than "big portions". Anecdata: I very rarely eat in the restaurants (less than once a month), I eat pretty small portions, I am physically active at least 5 days a week, still have extra weight which is hard for me to get rid of. There are reasons for that, but saying it's all explained by "portion sizes are too big" is very simplistic and misleading. There are many other factors.

The article claims two competing theories of obesity: the energy-balance and the carbohydrate-insulin model. The energy-balance theory isn't much of a puzzle, as you say. The puzzle is rather how to reconcile these two theories. According to the article, fructose is the unifying factor. Eating more fructose drives increased appetite and lowers metabolism. This feeds into the energy-balance mechanism, causing obesity. To your point, the higher appetites caused by fructose are incentivizing restaurants to offer larger portion sizes.

> Remember peak "Super Size Me"? By the time that movie had come out, portion sizes from McDonalds had already shrunk significantly. Then they removed the size option, but that wasn't the height of fast food consumption at all. It occurred at least two to three decades prior.

You can always order two big macs to make up for it.

Source: recovering junk food addict.

Reply on news.ycombinator.com