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Science

Fructose Isn't Just Sugar. It Acts More Like a Hormone (scienceblog.com) 69

Slashdot reader smazsyr writes: A new review says we've had fructose wrong for decades. The nine authors, led by Richard Johnson at the University of Colorado Anschutz, argue that fructose "is not just another calorie." It is a signal. It tells the liver to make fat and brace for a famine that never comes. That made sense for a bear fattening up on autumn berries. It makes less sense for a person drinking soda in March.

The review reframes the WHO's sugar guideline, argues ScienceBlog.com, as "less a recommendation about calories and more a warning about a signalling molecule we have been dosing ourselves with, several times a day, for most of a century."

Fructose Isn't Just Sugar. It Acts More Like a Hormone

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  • by Anonymous Coward
    You should be eating mostly meat.
    • by AlanObject ( 3603453 ) on Saturday April 18, 2026 @01:55PM (#66100294)

      Successful low-carb dieter here.

      I would have agreed with this at some point but as my experience with nutrition grew and I got older I have a more complete understanding.

      If your sole goal is to lose weight then eating nothing but meat works and it solves a lot of nutritional problems we tend to accumulate in modern living. Like fructose and high fructose corn syrup. Highly refined carbohydrates of all sorts. Trans-fats reduced to natural trace amounts. If you are on a meat-only diet you miss out on all that. You also find out that "saturated fats clog your arteries" and "salt raises your blood pressure" and yada yada all sorts of accepted wisdom is flawed at best and outright wrong.

      But because people have some success on lo-carb they tend not to recognize the nutritional deficits associated with modern living lo-carb. We don't tend to eat organ meats such as kidneys and liver and brains and so on, and instead focus on muscle meats. If you ate a whole rat like a coyote you would get most of the nutrients that animal had but we don't do that and not even close. We do better with eggs and seafoods in that regard. At the end of the day you aren't eating the way your body evolved to eat.

      So those nutrients you don't get from "modern" lo-carb come from other sources, including fruits, nuts, leaves. The key of course is not to exceed your calorie limit because if bodyfat is your concern the war is won or lost being able to sustain a calorie deficit or equilibrium over long term. When you get rid of most highly refined carbs in your diet you find it is much easier than you might have thought to just eat less and exercise more.

      ... worth what ya paid for it.

      • Bad of the week (Score:5, Informative)

        by will4 ( 7250692 ) on Saturday April 18, 2026 @02:13PM (#66100316)

        Since President Eisenhower's 1954 heart attack, activists found that attacking food can be done for profit, research funding and filling news articles.

        Name a food group, food additive, type of diet, regional cultural spices, miracle berry of the year, processing method, packaging method, etc. and there have been one or more attacks/ warnings, for fun or profit, against it.

        https://pmc.ncbi.nlm.nih.gov/a... [nih.gov]
        The saturated fat Controversy: Finding calmness in chaos

        Reading: "Make Room, Make Room" https://en.wikipedia.org/wiki/... [wikipedia.org]!

        • Name a food group, food additive, type of diet, regional cultural spices, miracle berry of the year, processing method, packaging method, etc. and there have been one or more attacks/ warnings, for fun or profit, against it.

          What does this prove? There have been recent attacks, for fun or profit, against the notion that the earth is round.

      • My experiences mirror what you are saying.

    • That's what I used to tell my ex...

    • Re:Don't eat fruit (Score:5, Informative)

      by walterbyrd ( 182728 ) on Saturday April 18, 2026 @04:08PM (#66100444)

      According to the article in scienceblog:
      - The Body Makes Its Own [fructose]
      - Does fruit cause the same metabolic damage as soda?
      -- No, and the review is careful on this point. Whole fruit contains fructose, but it also contains fibre, flavanols, vitamin C and potassium, all of which slow fructose absorption or blunt its downstream effects. The dose is also lower and the delivery slower. Fizzy drinks, by contrast, deliver a concentrated fructose bolus fast enough to overwhelm the small intestine’s protective filtering.

    • I know several very healthy vegetarians would disagree with you. And I know of many more, including the Shaolin monks.

      Maybe being omnivores gives us some options?

      • The Inuit likely have different dietary requirements than a Mediterranean tradesman which is likely different than a south Asian farmer.

        I doubt Inuit could succeed on a vegetarian diet like a south Asian farmer could.
        I doubt a south Asian farmer could succeed on a carnivore diet like an Inuit could.

        I don't see much discussion of this possibility when discussing diet. Nutrition discussions seem to treat all people as identical and they are most assuredly not.

        • Re:Don't eat fruit (Score:5, Interesting)

          by Aighearach ( 97333 ) on Saturday April 18, 2026 @09:17PM (#66100692)

          The Inuit have a short lifespan. They culturally disagree that heart failure resulting in death in your 50s is a disease; they consider that dying from old age. And communities will reject doctors that diagnose heart disease, other than in cases like malformed valves. Anything diet and lifestyle related they reject as a disease.

          Resulting in low-information people who like to repeat what they heard thinking they're immune to heart disease, because they have a lot diagnosed rate.

          Any time a population is claimed to be immune to lifestyle effects, or have results counter to other populations, check their lifespans; if they're not living longer as a result, it's always going to be an issue with diagnosis.

  • Who's "we"? (Score:4, Insightful)

    by haruchai ( 17472 ) on Saturday April 18, 2026 @01:45PM (#66100272)

    I've been hearing & reading similar things about fructose for decades, within about a decade of public awareness that school kids even relatively active ones were getting remarkably fatter very quickly

    • Willing to bet they're not giving "school kids" anything that resembles fruit.
      • Why not, they do! Note that the article is from the US, thus each pizza (but only frozen) is a serving of vegetables, and because tomato is a fruit, the frozen pizza also counts.

      • by znrt ( 2424692 )

        doesn't matter. shakes, cakes and syrup are worse, but fructose in regular fruit is still bad in excess (obesity, diabetes, liver problems). the benefits of fruit are many: antioxidants, vitamins, minerals, etc. (excess of some of those can be bad too, mind) but mainly because of the high fructose content it should be consumed sparingly. like tfa points out we're not bears going into 6 months of hibernation, even though [-space reserved for obligatory joke-].

        fruit today is overabundant, even already peeled

        • Re:Who's "we"? (Score:4, Interesting)

          by StikyPad ( 445176 ) on Saturday April 18, 2026 @06:26PM (#66100546) Homepage

          People act like life expectancies have been getting shorter.

          They romanticize historic and prehistoric diets alike, as if they were utopian; as if people somehow intuited what to eat, or else that the constraints of supply somehow shaped digestive evolution like an intelligently designed metabolic symphony of symbiosis. That ignores the plain reality of volatile supplies -- even after the advent of agriculture, but especially before it -- and the reality that evolution is not driven by perfect health or life expectancy; only by surviving long enough to reproduce.

          Even if modern diets are "unhealthy" (whatever that means), that doesn't imply that people were eating healthier at any point in the past. In fact, skeletal records clearly show that human existence has been rife with scurvy, rickets, iron deficiency, and stunted growth. Nutritional deficiencies were the norm, not the exception. Now (many people) have abundance, and that presents its own challenges, but the notion of an ideal, historic nutritional baseline is pure fiction. It's turtles all the way down.

          • by znrt ( 2424692 )

            Even if modern diets are "unhealthy" (whatever that means)

            in this case "unhealthy" means fatty liver and possibly steatohepatitis, high lipoprotein in bloodstream, heart disease, hypertension, insulin resistance, gout. and getting fat in general, which is unhealthy on way more accounts than i'm ready to list.

            but the notion of an ideal, historic nutritional baseline is pure fiction

            i agree, i'm not a paleodieter, that's nonsense. i responded to "nothing they give to school-kids resembles fruit" which sort of implies that fructose from something that resembles fruit is okay because "it's natural" (in the same line of argument you critizis

        • Apples keep very well when refrigerated. 6 months is easy and some will be good even after a year.
    • 30 or 40 years ago Durk Pearson & Sandy Shaw suggested fructose as superior to sucrose because fructose is sweeter, therefor less could be used. Apparently food manufacturers switched to fructose without reducing the amount of sugar.
      • by haruchai ( 17472 )

        huh, the 2 "life extension" and antioxidant megadose nutters who died at 81 & 78?
        so no better than US median age of mortality.
        we're better off living like Churchill who died at 90

        • huh, the 2 "life extension" and antioxidant megadose nutters who died at 81 & 78?
          so no better than US median age of mortality.
          we're better off living like Churchill who died at 90

          Not nutters; just unfortunate.

          Sandy had several systemic health problems on and off for decades; but nothing caused by Life Extension regimens.

          Durk died of a simple foot (IIRC) Infection that, due to his remote location, eventually turned into Septic Shock; again, nothing to do with his Life Extension efforts.

          • by haruchai ( 17472 )

            large amounts of antioxidants have been shown to make cancer *worse*. it can't be said for certain that megadosing with them didn't hasten her demise

            • large amounts of antioxidants have been shown to make cancer *worse*. it can't be said for certain that megadosing with them didn't hasten her demise

              Frankly, I don’t know. She was always somewhat quiet about herself.

              And I haven’t closely followed much Life Extension Research for a couple of decades.

              Fortunately or Unfortunately, the Pearsons practiced what they preached; at some point the “well I wish I hadn’t.dones” may begin to outweigh the “hey, that really worked”s!

              Not nutters; their CVs and resumes prove that; but unfortunately, they kinda exemplify why I say “A Mind is a Terrible Thing”. . .

  • That's it (Score:5, Funny)

    by Waffle Iron ( 339739 ) on Saturday April 18, 2026 @01:47PM (#66100278)

    From now on, I'm only drinking soda in October.

    • by tlhIngan ( 30335 )

      From now on, I'm only drinking soda in October.

      You might be referring to Mexican Coke, but American Coke did go back to using cane sugar.

      The problem is, though, Fructose isn't a stable sugar in acid - it breaks down to glucose. It takes about 2 weeks for it to do so, after which it gets much harder to tell if it used cane sugar or HFCS even with a mass spectrometer. There are tells, but you're starting to dig into the noise for that. It's about two weeks at room temperature - if you warm it up it speeds up,

  • BS (Score:4, Interesting)

    by groobly ( 6155920 ) on Saturday April 18, 2026 @01:52PM (#66100286)

    Article is paywalled, but from the abstract the assertion of hormonal action appears to be hype BS. Only the liver can metabolize fructose. That's the main issue with fructose.

    • Re:BS (Score:4, Informative)

      by nospam007 ( 722110 ) * on Saturday April 18, 2026 @02:07PM (#66100310)

      Just get the Archive Page extension, then no paywalls anymore.

    • by dfghjk ( 711126 )

      "...but from the abstract the assertion of hormonal action appears to be hype BS. "
      The research paper is not what was cited for any "hormone" comment, the second link was. And it's not paywalled and says "like a hormone", not "hormonal". There is no claim that fructose IS a hormone or has hormonal action.

      "Only the liver can metabolize fructose."
      That has been recent conventional belief, but there is data that suggests otherwise.

      "That's the main issue with fructose."
      It is not, perhaps you should read the in

      • Everything is a poison if you injest too much of it, even water. The small amount of fructose in fruit is harmless, the ridiculous amounts in fizzy drinks etc, not so much.

    • See also Johnson, RJ The fructose survival hypothesis for obesity [nih.gov].
    • This seems to be the open-access link [waltersport.com] but in searching for that I saw another article from the authors about the small intestine metabolizing fructose into glucose.

      So it's probably more complex than we thought. Another 5-6-fructase pathway, I'd guess, haven't read it yet.

  • In humans and other mammals, sucrose is broken down into its constituent monosaccharides, glucose and fructose, by sucrase or isomaltase glycoside hydrolases, which are located in the membrane of the microvilli lining the duodenum. The resulting glucose and fructose molecules are then rapidly absorbed into the bloodstream.
  • People like to say fructose is horrible, but it's in just about everything, even "natural" foods. For more information, listen tothis excellent podcast.
    • by znrt ( 2424692 )

      it's all about the dose. and it appears you forgot the link.

    • In other news, people like to say that nuclear radiation overdose is horrible, but everything is radioactive, even "natural" foods like bananas.

      For more information, subscribe to my excellent personal newsletter. (published once every 87.7 years, don't miss the next one)

    • Yeah...and THC extract is the same as the natural source... except that the psychotic effect is countered by the natural anti-psychotics in the natural source. or whatever other example one can think of where the natural source is balanced or so tiny it doesn't matter or never gets so much exposure over a lifespan to become significant (until we put it into everything).

  • by 93 Escort Wagon ( 326346 ) on Saturday April 18, 2026 @02:40PM (#66100350)

    But it's important not to overreact until there have been more studies which confirm (or refute) it.

    Jumping the gun, building your belief system based on single "out of left field" study results, gets you RFK Jr.

    • That's true, but this study isn't "out of left field" at all, it's an expected result and there have been lots of studies suggesting problems with HFCS. There's also a lot of industrial propaganda that floods the space with repeated studies designed to "fail" to find a difference.

  • Fucktarded: I'm gonna eat whatever and disregard evolution Evolution: I go both ways, and right now I'm the top.
    • No one said you had to change your diet; the authors are just presenting the information that they found. Use it or don't.

      But I'm going to guess that you're the sort that sees a "road closed" sign and says, "Screw that, I'm gonna drive anyway!" Which is fine, too, so long as you're the only one in the car.
  • This is basic physiology 101. I learned this 25 years ago : if you eat sugar, whether sucrose or fructose, the brain understands that our body probably encountered a big bush of food and itâ(TM)s time to store the energy for later use. Thatâ(TM)s called building fat. thatâ(TM)s what the insulin hormone does.
  • just because this is published under the Nature umbrella doesnâ(TM)t make this science. This is an Op Ed from a nephrologist who literally has a book (or three) to sell. from his own autobiography: Richard J. Johnson, M.D. is Emeritus Professor of Medicine a at the University of Colorado since 2008. A graduate of the University of Wisconsin, Madison, with a major in Anthropology, and a graduate of the University of Minnesota Medical School, Minneapolis, he is a physician and nephrologist whose resear
  • It's not news that fructose is believed to be more of a devil in your diet than sucrose. But they commonly appear together. Here's a table I found of the ratio in some fruits. Then there's "HFCS" or High Fructose Corn Syrup, which typically has either 42% or 55% fructose [wikipedia.org], the rest being glucose (and about a quarter water.) As there are a number of fruits with a higher percentage of fructose than HFCS, the problem isn't really the percentage, it's the quantity.

    The biggest problem with HFCS isn't that it's us

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