Fructose is the main culprit of the obesity epidemic: study | Hacker News Reader

Fructose is the main culprit of the obesity epidemic: study

studyfinds.org

60 pointsBrajeshwar119 comments

There's a full text PDF (I think a preprint?) of the study over here:

https://royalsocietypublishing.org/doi/10.1098/rstb.2022.023...

Abstract:

  The fructose survival hypothesis proposes that obesity and metabolic disorders may have developed from over-stimulation of an evolutionary-based biologic response (survival switch) that aims to protect animals in advance of crisis. The response is characterized by hunger, thirst, foraging, weight gain, fat accumulation, insulin resistance, systemic inflammation and increased blood pressure. The process is initiated by the ingestion of fructose or by stimulating endogenous fructose production via the polyol pathway. Unlike other nutrients, fructose reduces the active energy (adenosine triphosphate) in the cell, while blocking its regeneration from fat stores. This is mediated by intracellular uric acid, mitochondrial oxidative stress, the inhibition of AMP kinase and stimulation of vasopressin. Mitochondrial oxidative phosphorylation is suppressed, and glycolysis stimulated. While this response is aimed to be modest and short-lived, the response in humans is exaggerated due to gain of ‘thrifty genes’ coupled with a western diet rich in foods that contain or generate fructose. We propose excessive fructose metabolism not only explains obesity but the epidemics of diabetes, hypertension, non-alcoholic fatty liver disease, obesity-associated cancers, vascular and Alzheimer's dementia, and even ageing. Moreover, the hypothesis unites current hypotheses on obesity. Reducing activation and/or blocking this pathway and stimulating mitochondrial regeneration may benefit health-span.

This is a crackpot paper.

Care to elaborate?

Maybe so, but please don't break the site guidelines like this. They include:

"Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something." - https://news.ycombinator.com/newsguidelines.html

Perhaps you don't owe papers you consider crackpot better, but you owe this community better if you're participating in it.

The only relevant part however:

> Richard J. Johnson has received honoraria from Horizon Pharma and has stock with XORTX Therapeutics. Richard J. Johnson, Laura G. Sánchez-Lozada, and Miguel A. Lanaspa also have equity with Colorado Research Partners, LLC.

This has been known for a long time. Watch "Sugar: the bitter truth": https://www.youtube.com/watch?v=dBnniua6-oM

The main problem is that fructose is added in almost every product in the US.

Seems disingenuous to say "fructose" is the problem. "High fructose corn syrup as an additive in everything" is different than just "fructose", which is naturally found at reasonable levels in fruit - a very healthy and beneficial part of our diets.

Too much fruit isn't healthy, though. It's widespread myth that you can't eat too much fruit. Depends on the type of fruit, too.

It's less so a myth, and more so that the Western diet tends to eat so little fruit that even suggesting that you can eat too much would lead to people eating even less than they currently do, worsening outcomes.

It is a double edged sword though, because a LOT of people, including many health-conscious people, think of fruit and fruit juices as equivalent when they very much are not. You can drink down 4-7 apples/oranges/etc worth of nutrient-rich sugar juice in a matter of minutes, with only a fraction (or effectively zero) fiber. Quite terrible for the kinds of insulin and leptin resistance, ATP disrupting effects discussed in the paper. It's also worth remembering that many types of modern fruits are extremely sugary and tend to be relatively less fibrous and nutrient dense than historical, wild, and heirloom varieties.

"Eat whole fruits regularly and in moderation" is much better advice overall. Simple, to the point, and cuts out problematic ambiguities.

There is plenty of evidence that fruit does make us fat. The basis is that fruit used to be seasonal and was related to mammals surviving winter:

> We have some local hatcheries, so at the time, we were getting significant runs back, and so they were willing to provide the salmon. Obviously, I don’t have enough students on board to go pick huckleberries in the amount that big grizzly bears or brown bears would want to eat. But we have an apple orchard right next door that is very — the apples are very, very similar in terms of being a lot of water, high carbohydrate and not too much else. We started doing studies where we would feed bears, if we’re talking about salmon, all the way from just maintaining their weight up to gaining prodigious amounts, and the same on apples. And then, so the next thing we did was feed both apples and salmon. And we let, in a lot of studies, we let the bears just determine what that mixture would be. And when they mixed them on a daily basis, then they gained more weight per unit of energy intake than either salmon alone or apples alone. And so there was an interaction effect, where by consuming both foods, it actually provided a better diet than either food alone. And that was what we were seeing in the wild bears. So the captive bears, given the choice, would do exactly what we were seeing in the wild bears.

https://www.ktoo.org/2022/10/13/bears-eat-far-more-berries-t...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6518666/

> Conclusions: Current evidence suggests that whole, fresh fruit consumption is unlikely to contribute to excess energy intake and adiposity, but rather has little effect on these outcomes or constrains them modestly. Single-meal RCTs, RCTs lasting 3–24 weeks, and long-term observational studies are relatively consistent in supporting this conclusion. Whole, fresh fruit probably does not contribute to obesity and may have a place in the prevention and management of excess adiposity.

In a world where there is sugar in essentially everything, I would agree that it would be difficult to find a correlation between the effects of fructose in fresh fruit added to a diet and without it.

I shouldn't have said "does" but "can" would have been more appropriate.

It's way harder to eat a lot of whole fruits though. 1 gala apple is 80 calories, you need something like 25 apples to fulfill the calories of the day without getting fat. That's a lot of apples and the glucose + fructose + fiber combo triggers your brain in feeling satiated for a good chunk of time (2 hours roughly), with just 1 apple.

Granted that this is all extremely specific to an individual, I can easily eat 2 cheeseburgers in a meal and just feel full, or 2 apples and feel full, 2000 vs 160 calories!

"show me your fat fruit friend" https://youtube.com/shorts/EL4LY1WPEes

Lol that killed me, ahahah

Fructose specifically is the problem. It has completely different metabolism compared to glucose. It's explained in the above video, starting from around 43:00.

Also, one of its effects is that it increases appetite.

In nature, wherever you find fructose, you find extremely high fiber. The fruit we eat is only so sweet from centuries of genetic modification.

This is a cruel aspect of the human body IMHO. Our ancestors went through hell to get us to the point of caloric abundance on the tech tree and our bodies are like, nah, not good enough, we liked starving better! :-)

Is anyone having flashbacks to when fat was vilified and the food pyramid put bread at the bottom?

Bread doesn't have fructose, right?

Most bread sold in the grocery store has high fructose corn syrup

(in the USA)

Do you have any data to back that assertion?

In my limited searching I found an article that says the opposite, but they also don't provide any data[1]

[1] https://www.msn.com/en-us/health/nutrition/secrets-of-store-...

#10. https://www.healthline.com/nutrition/foods-with-high-fructos...

It would be nice if there was a database of food labels.

You can find this info on https://fdc.nal.usda.gov/

The search function and UI is terrible, though. There used to be a website self.nutritiondata.com that was amazing. Full calorie, carb, fat, and nutrient profiles on all manner of whole foods, plus lots of branded processed food labels as well. Apparently they had to take it all down because it was out of date. They got all of their info form the USDA link above, so the data still exists and there are other web apps out there that organize it for you, but they all pale in comparison to the old self.nutritiondata, sadly.

The packaged, pre-sliced stuff from brands, yeah.

Most grocery stores also have a bakery though, and its far less common there.

Sucrose is broken down in the stomach (by the low pH) and small intestine (by sucrase) into a 50/50 mix of glucose and fructose. The most common high fructose corn syrups are (to a first-order approximation, after dehydration) 58/42 and 45/55 mixtures of glucose and fructose.

I'm not saying HFCS is good, but a sucrose-sweetened bread is likely just as bad for you as an HFCS sweetened bread, if the mass of sweetener is the same.

Edit: When I was at Google, I remember some employees complaining that the only free sodas were either HFCS-sweetened or artificially-sweetened. So, we later got some agave-sweetened free sodas. The things is agave nectar is 56% fructose. The most common HFCS grades are 42% and 55% fructose. Maybe agave nectar is maybe marginally more healthy, but really... if you're going to get that worked up, you're much better off training yourself to be content without the free soda. Drink soda, or not, but please don't fool yourself into thinking switching from 55% fructose to 56% fructose is a health intervention. Maybe people are afraid of trace residues from the HFCS processing, but all evidence suggests that the fructose is orders of magnitude more harmful than any ingested byproducts of the HFCS manufacturing process.

Yeah, I could never reconcile the concept of a "balanced" diet and the idea that a certain, easy to produce, category of food should be the majority of calories. It was clearly a nudge on the exploding post-war populations to eat foods that are good for business and not necessarily good for health.

An acre of corn or wheat makes whole lot more than that same acre being used for leafy greens or grass-fed proteins and fats (i.e. livestock)

Modern dietary guidelines still put breads at the bottom, the Harvard Healthy Eating Pyramid is a really good version of the "pyramid infographic" style of nutritional guidance. There is some evidence the old US food pyramid guideline of 5-11 servings of grains were influenced by lobbying from the food industry, however by my calculations 5-11 servings of grains is pretty much necessary if you follow the AHA's optimal health guidelines of 300 minutes of cardio per week.

If you look into the history of how the US food pyramid got made the biggest influence of industry lobbyists were on the meat and dairy recommendations, changing "no more than 2-3 servings" to "2-3 servings a day" and removing red meat from the "sparingly" peak at the top of the pyramid.

This was a problem well before the "Food Pyramid": Food Calories and the Standard Calorie Model were invented by the "scientists" at the Sanitarium at Battle Creek (aka "Wellville") who were also "coincidentally" the founders of Kellogg's and the National Biscuit Company (Nabisco) based on some weird religious beliefs that grains were God's true foods. Food Calories were invented to sell more cereals, crackers, and cookies.

Calorie is a unit of energy equivalent to the heat energy needed to raise the temperature of 1 gram of water by 1 °C (now often defined as equal to 4.1868 joules).

How was that invented to sell oreos?

That's the definition of "little-c" calorie, not food Calorie. Food Calorie still claims a relationship to "little-c" calorie but its scale is in a further different magnitude and some of the numbers in its standard model can't be replicated so are just taken as given constants. But also the SI system dropped little-c calorie for Joules in part to shake up the over-reliance in some of the sciences of old bad Phlogiston theories, that "heat energy" is somehow usefully more indicative of energy density. (The physics formula for energy density of mass is the well known E=mc^2, nothing to do with heat.)

Over-focusing on "heat energy" and a model that assumes the human body is an ideal spherical furnace ignores most, if not all, nuance in macronutrients and metabolism pathways, and biases in favor of foods that aren't as easy to set on fire (such as grains over fats). (Not to mention the very dark flipside of "exercise calories" and that if you are optimizing the human body's output as an ideal spherical furnace you are optimizing for states such as "fever" and "stroke".)

Bit of a side note on grains being "God's true food" - I read a book about the formation of the earliest states (Against the Grain by James C. Scott) where the author argues basically that grains prevailed as states developed because of their suitability as a currency for taxation compared to other staples like potatoes/root vegetables. Grains are usually harvested all at once at predictable times (so harder to lie to tax collectors), have a relatively long shelf life, and are easy to weigh/standardize. I believe they're also more laborious to grow which might benefit a fledgling state trying to maintain control over its subjects.

The author has a noted anarchist bent, but definitely an interesting read and that take is kind of a funny parallel with the "God's true food" rhetoric.

Probably 20 years ago now when I was reading about sugar and atkins diet some rando on the internet suggested that high intake of sugar told our bodies (or at least my scandanavian/scottish-genetics body) to start bulking up for the winter. Looks like rando might have been right.

There's also the theory in Survival of the Sickest by Moalem that the high blood sugar in diabetes acts like antifreeze and protects against frostbite in the winter. That was from 2007, I don't know what people think about that theory now. (EDIT: After looking it up it looks like Moalem was talking about type 1 Diabetes which makes no sense to me at all since historically T1 was a pretty immediate death sentence, and I can't find any decent scientific papers citing that book, its all garbage, oh well).

Those theories have always been intuitively compelling to me and stuck in my head.

I think you should take any summary of a study from this guy that isn't based on your own conclusions from the experiment and data with a grain of salt because the dude blames fructose for everything. It might be the root of all evil but I'm wary of this being like seeing blood at every murder scene and saying it's the cause.

Like I really want him to be right and it usher in an era of better health and medical outcomes from a fairly straightforward change to diet but there's as many theories as there are people studying the issue. The only thing that we can do now is verify it experimentally. If you're looking at the paper that's the "Testable Predictions" section.

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.

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...)

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."

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.)

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.

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.

> 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.

Not smart enough to comment on the science but a pet peeve of mine is

> When humans are hungry and running low on active energy, our bodies enter survival mode

We are always in “survival mode.” Using that term instead of describing the changes occurring (do our cells change their metabolic pathway? Are certain processes suspended?) is very lazy writing.

There are lot of food products that advertised as “healty”, “bio” etc, most of them explicitly mention that they use fructose instead of sugar. People are really made to believe that fructose-based candies are much healthier than sugar-based ones.

US sugar consumption peaked in 2000 and has since declined, with the decline being driven primary by a decline in HFCS: https://www.ers.usda.gov/data-products/chart-gallery/gallery...

Yet the obesity and Type 2 Diabetes epidemics have only gotten worse, with the diabetes epidemic reaching what appears (in this graph) to be an inflection point around the time sugar consumption started to decline (which makes sense when you realize it entails a shift to more fat consumption, including saturated fat): https://www.ncbi.nlm.nih.gov/books/NBK568004/figure/ch3.fig2...

I'm amazed that here we are, in the third decade of the low-carb era, with the obesity rate now hovering over 40% despite a decline in sugar consumption, and this nonsense is still being taken seriously, let alone by people (like HNers) who think they're well-informed.

BTW go look at photos of Johnson and Lustig: they're both fat, unlike Barnard, McDougall and other doctors who advocate ultra low-fat, whole food, plant-based diets.

It is also the cause of all the fatty liver issues we have now.

You can just cut out all plant-based calories from your diet entirely and you'll find that you will almost effortlessly get in shape. All the vitamins and nutrients that your body needs are available in animal-based foods, including vitamin C (fresh meat contains vitamin C) and in fact they are in a more bioavailable form, meaning that they are easier for your body to extract and absorb. From a health and fitness perspective a diet of meat, fish, and eggs is perfect. You'll also find that you can't stand alcohol if you follow this diet.

Please link research to these claims.

The research is a never-ending rabbit hole. I've told you what the situation is and you can either try it for yourself or live sub-optimally.

I live sub-optimally in so many different facets of my life that trying to bring them up all to optimal would be a never-ending endeavor. My life is still pretty good though -- so... I guess I'll live sub-optimally?

I guess you will

Except that if you have problems with digesting dietary amines you will quickly find yourself miserable. Also putting yourself under a very large methionine load.

Everyone on Earth would thrive on a diet of only fresh red meat. I'm sorry you don't see it that way. A lot of people have made up ideas in their heads that cause them to be miserable and I'm not sure what to do about it.

So should we stop eating fruit? what's the actionable takeaway here for someone already avoiding high-fructose corn syrup?

Avoid sugar, regardless of whether it is added sugar or not.

Sucrose is effectively 50% fructose.

And the supposed benefits of fruits are pretty much non-existent.

Fruits, when consumed in moderation, also contain fiber and phytonutrients, hardly non-existent benefits.

Humans can thrive on meat alone without any problem.

No fiber and no phytonutrients. The supposed benefits of both are basically hypotheses with really crappy observational data to support them.

If anyone is still reading this, I would not suggest taking dietary advice from this poster. Talk to a nutritionist about your specific needs instead.

Even citrus fruits for Vitamin-C?

There are plenty of sources for vitamin C, and there are better sources for significantly less sugar.

This is lazy either/or thinking; sugars are fine, excess sugar causes issues over a longer timespan.

That's a tautological statement.

Excess of anything is harmful by definition (otherwise it is not in excess).

The only question is how much is too much.

Fruits contains a lot of dietary fibers which lower the side-effect of fructose.

Also, fructose itself is not in such a high dose in an apple, you are far away from fructose syrup concentration which was added to everything pretty much at the same time the obesity epidemic has started.

Finally, fruits contains a lot of other beneficial nutrients, so benefits outweigh the harm fructose can do to you.

We metabolize fructose fine in reasonable doses and with fiber. It has been part of our diet for thousands of years.

It's not just the fructose. Any raw sugar is bound to have nasty-side effects. Our wheat flour is too processed, so the bread and pasta is not great for us as well. But a bit of whole pasta and bread will not spike your insulin level much.

We are, as usual, overdoing it.

It's unfortunate naming similar to "fat". Most fruits are really not that high in fructose, compared to stuff like high-fructose corn syrup (well, it's in the name) that's widely added to beverages and other processed food.

The fructose-glucose ratio of a lot of apples is almost 2:1. HFCS is usually 45-55% fructose. Watermelon has a similar ratio. Lots of fruits have a higher fructose to glucose ratio.

HFCS is called high-fructose not because its some incredibly high level of fructose compared to most everything else, its because compared to regular corn syrup it is high. Regular corn syrup is nearly 100% glucose, so a mixture of 45% or 55% fructose is extremely high in that context. Table sugar is 1:1 fructose/glucose, but we don't call it high-fructose table sugar.

It's not the ratio that hurts you but the absolute dose you ingest.

They were probably talking ratio, not total amount.

> Most fruits are really not that high in fructose, compared to stuff like high-fructose corn syrup

An apple is going to have like 19g of sugar. So a little over 12g of fructose. A serving of Buffalo Wild Wings Asian Zing sauce (2tbs) has 19g of sugar. I don't know what variety of HFCS, so we'll assume HFCS 55. That's 10.45g fructose.

So an apple has more fructose (total) than a few buffalo wings with HFCS-based sauce.

Not a chemist here, so I'm wondering which is the higher energy state: fructose+glucose dissociated (into HFCS), or bound together into sucrose (white table sugar).

https://en.m.wikipedia.org/wiki/Sucrose

Why doesn't either HFCS want to crystallize into sucrose, or sucrose want to melt into 50% HFCS, given a bit of time, water, heat, or stirring?

I don't doubt there's a lot of metabolic differences between sucrose and HFCS. Given they're free instead of bound I imagine it hits the body differently, and some studies do suggest this. Gastric acidity easily breaks the bond though, it rapidly converts to glucose and fructose in the gut. So I imagine most changes would be with our body's early detection in the eating process, such as the taste buds and other senses like that.

I realize I never really answered your other question. Its tricky sticking the two sugars back together into sucrose, as heating it will generally carmelize it. After all, when you carmelize sucrose you're breaking that bond and oxidizing the glucose and fructose, so heating HFCS will ultimately yield the same thing in an oxygen environment. You'll generally need some kind of chemical process to link it together, it takes a bit of extra energy to join the two sugars back together.

Sucrose will hydrolize and break apart in water on its own, but it does take some time. Adding a little bit of acid will rapidly break it apart.

HFCS is available in ratios with up to 90% fructose. Granted, I don't know what the average is in the food industry. But like other commenters said, it's mostly about the absolute amount. You can't realistically eat enough apples to reach a fructose intake equivalent to that of a sugary drink. And even if you do, you also ate lots of fiber and other good nutrients.

Therefore, worrying about fruits because of fructose is unwarranted. Well unless you have fructose intolerance.

> Granted, I don't know what the average is in the food industry

The average is usually 45-55. By far the most common variety is HFCS-55.

I'm not disagreeing with the idea its easier to pound a lot of sugar drinking sweet beverages. I'm just disagreeing with the concept "fruits don't have much fructose" and people thinking HFCS means its generally way higher fructose content than other common sugars. An apple has more fructose than a serving of BWW Asian Zing sauce, as I pointed out in another comment. I'm not arguing wings are healthier than apples, I'm just pointing out the raw numbers of sugar. A cake made with sucrose will have a similar amount of fructose ratio as cake made with HFCS, assuming similar amounts of total sugar content.

Would taking a fiber supplement or some psyllium before eating sugary snacks help, I wonder?

Measure your blood insulin level while doing so and you'll get the answer.

Works for me to eat a banana before I eat white pasta: I get less tired.

YMMV. But it's always better to stick to healthier meals if you can.

I know I can't. I got a sweet tooth.

> Fruits contains a lot of dietary fibers which lower the side-effect of fructose.

Are they actually mitigating the side effects, or adding bulk/satiety so you don't eat as much? It's unclear how dietary fibers mitigates the following:

>fructose reduces the active energy (adenosine triphosphate) in the cell, while blocking its regeneration from fat stores. This is mediated by intracellular uric acid, mitochondrial oxidative stress, the inhibition of AMP kinase and stimulation of vasopressin. Mitochondrial oxidative phosphorylation is suppressed, and glycolysis stimulated.

Mitigating. They slow down fructose absorption, and nourish the macrobiotic that in return also help.

tl;dr - Limit processed sugars, eat significant amounts of fiber.

Nobody is saying that; it's not an either/or, or a dichotomy. The issue, as always, lies in overconsumption.

Part of that is down to manufacturers, who especially in the US put loads of sugar in pretty much everything. Part of that is down to the consumer, which chooses convenience over awareness; part of that is things like take-out or drinking culture, but part of that is also diet culture, a diet telling you "stop eating this, only eat that". That too is convenience.

As is calling certain foods "healthy" vs "unhealthy", because that's no absolute either, and it's a lazy descriptor - as in, "please explain to me why it is healthy / unhealthy". The crux of it is, nothing is healthy or unhealthy unless it's literal poison, it's more about calorific content and quantities.

You can’t seriously be blaming consumers for this. It’s not consumers’ job to be scientists and understand whether some factory made ultra processed food is good for them or not. This is entirely because the government is bought and paid for by capitalists that lobby it to allow large corporations to sell garbage to people.

The solution is a simple number on food (1-100) that tells a consumer how healthy (or not) a product is and takes into account caloric content, additivies, sugar content, etc. This is something the government should be doing but since the US is governed by radical conservatives that are immensely corrupt it’s likely not going to happen. There is an app I’ve recently started using called Yuka that does this.

I’m also not opposed to banning certain categories of unhealthy products entirely.

Your point about overconsumption is valid but again, I don’t believe this is the fault of consumers, this is just a result of the capitalist system which encourages overconsumption in order to keep the system from falling apart.

>The solution is a simple number on food (1-100) that tells a consumer [...]

What's the evidence on interventions like this? We tried adding calorie counts on packaging and menus, but obesity rates are still going up.

Nutriscore exists since a while in France. It’s rate food from A to F.

Not sure of the utility of that.

But I rely very much on the calorie count!

This makes the demonstrably false assumption that what's good for you, today, is good for everybody, all the time.

Different bodies need different things, and no single dumbed-down number like that can ever take that into account.

What we need is better ways of making clear just what those needs are to people, which ultimately comes down to better education. Is it a quick solution? Absolutely not. But it's the only one that can genuinely help people to improve their own health through nutrition.

That said, we can also improve our regulation around these things based on the best science we have available, to do things like ban or require labeling and appropriate disclosure of substances that are known to be universally or commonly harmful.

Not fruit, but rather fructose and other diets contributing to fructose production. In the article and linked abstract (in a comment here), it said "process is initiated by the ingestion of fructose or by stimulating endogenous fructose production via the polyol pathway". I was curious about the "polyol pathway" and found this other study on "endogenous fructose production", https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6684314/.

Key takeaways: also avoid high glycemic and high salt diets. Basically avoid fast-food. Make your own meals. Eat less or no heavily processed foods. Watch your sugar and salt intake. Keep staying away from HFCS or corn syrup in general.

Apples, grapes, pears, and watermelon are particularly high in fructose. You could substitute low-fructose fruits like berries, cantaloupe, and oranges.

Many "healthy" snacks and desserts don't want HFCS on their labels so they use cane sugar, but that's a mix of glucose and fructose.

And foods with a high glycemic index like white bread, potatoes, and rice might stimulate endogenous fructose production.

You might think this study exonerates paleo diets, but there's evidence that excessive protein intake may contribute to gluconeogenesis, potentially increasing fructose production endogenously.

And even though apples are high in it, you have to eat a silly number of them to get the same sugar as in one drink.

Stop drinking a lot of fruit juice. We are outsmarting nature's packaging by doing that. Eat the whole fruit and the fiber comes along with it.

No, but we should probably stop eating or cut back seriously on cookies, cakes, and other non-fruit sources of sugar.

No: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6518666/

What will we do without our candies and toys?

Cool! Nutrition now has its own GUT!

I hate stuff like this, everyone is different, period. Learn what works for you. I've tried every type of diet under the sun over the years. Plant based, vertical diet, carnivore, Ray Peat inspired, keto with and without plants, full carnivore...what works best for me personally is whole foods plant based (I don't do well with histamines) - on a typical day of eating I'll get somewhere around 400g of carbs and something like 15% of my cals from fat. I stay lean as hell, my body loves carbs, including a ton of fruit. If I feel like I need some meat, I eat it.

Who does high amounts of refined fructose syrup work for?

Do any of the diets you described advocate high doses of refined fructose?

Yeah, on a RP diet refined sugars including fructose from juices are encouraged.

Not too much to go on here without the paywall-locked pdf. That said, from the abstract it seems their model of obesity depends on fructose-caused hunger driving consumption of fat: "metabolic effects that result in the increased intake of energy-dense fats." Whatever that means.

It is true, I think, that most of our body fat comes from our diet, so at some level any theory of obesity ultimately has to come down to consuming fat. (Which also implies if you stick to a low-fat diet, you will not be obese. Though you might be miserable or unhealthy.)

At a population level, has fructose consumption been going up as obesity has increased? That could serve as a sanity-check of the theory. (I don't know the answer to the question, so it's a real question.)

This is the exact opposite of what I understood to be the case. I thought that if you eat more calories than you consume you store them as fat, it doesn't matter if what you consume is fat or not, in fact consuming fat can help because it takes longer to digest and keeps you full and you may eat less than if you are eating sugary things that digest quickly.

You're partially right. It's a complete fallacy to think that just because you consume fat, you store fat. Any fat you eat is broken down before going into the bloodstream, and is generally made available for the body to use as fuel in preference to being stored.

The reason you store fat is because you have insulin in your bloodstream, which is a messenger telling cells to store energy. Insulin is released into the bloodstream in response to blood sugar levels going up. So, in order to avoid storing fat, you should avoid eating sugar (and other foods that get converted into sugar quickly, like most carbohydrates). People tend to lose weight if they consume mostly fat, and that is largely because eating fat doesn't raise blood sugar levels, and therefore doesn't stimulate insulin secretion.

So it's more complicated than calories in minus calories out, and fat is good for more complicated reasons than it just taking longer to digest.

Fructose does have a bad effect. But that's separate from the above - fructose is even more bad than just it being a sugar.

> has to come down to consuming fat.

Consuming fat is not the only part of your diet that can result in body fat.

https://en.wikipedia.org/wiki/Lipogenesis

> It is true, I think, that most of our body fat comes from our diet

I am pretty sure your assumption is wrong. Stored fat has no correlation with the composition of your diet, but only with the amount of excess calories.

I don't think this is right -- my understanding is the fat tissue closely correlates with fat in the diet.

E.g., "Tissue and blood fatty acids, because they are mainly derived from the diet, have been used as biomarkers of dietary intake for a number of years."

from

"Fatty acid composition of adipose tissue and blood in humans and its use as a biomarker of dietary intake"

https://www.sciencedirect.com/science/article/abs/pii/S01637...

Of course, lipogenesis is a thing, but it only produces SFA or MFA -- not PUFA. I can't find a reference, but if I'm not mistaken obese people have a higher percentage of body fat as PUFA than non-obese people, which, if true, is another way we can tell a significant portion of their fat must be coming from the diet.

I guess it might be possible to eat sufficient quantities of high-carb, very-low-fat diet to drive enough lipogenesis to get fat, though I don't know if this actually happens in practice.

As one sort of silly example, people eating a pure potato diet lose weight easily, with no restriction on total calories.

> Not too much to go on here without the paywall-locked pdf

https://royalsocietypublishing.org/doi/10.1098/rstb.2022.023...

that works for me.

Wasn’t Steve Jobs a fruititarian?

Yea, he was totally obese a.f.

I think they key takeaway is the the word hypothesis is used quite a bit in the summary.

Actual fruits have much smaller amounts of fructose than you find in processed food sweetened with it. They also contain fiber to help digest it properly. Industrially, it's a concentrate.

Actual fruits often have a higher ratio of fructose to glucose than HFCS does.

I agree there's probably a lot more going on with fruits such as the fiber content and potentially total sugar content.

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