Comment by paimapi

1 day ago

sample size n=37 of which recruitment only happened in Shanghai without any real control for confounders, only evaluated over a period of two weeks with no longterm follow-ups, the dosage of 40g RS/d is very high (would take about 4-5 large potatoes daily for equivalency or ingesting likely expensive supplement), the crossover compares RS vs CS in the same participants with only a 4 week washout which is a weakness since fermentable fiber persists >4 weeks, also the supplement they used was industry-provided by a starch manufacturer which was weirdly not disclosed

this is a great study if you are an overweight/obese adult without overt metabolic disease, willing and able to consume 90 g/d of starch supplement within a controlled diet, and living in Shanghai with similar baseline fiber intakes endemic to that population. it is extremely not generalizeable to you or even me though I fit more of those characteristics than I care to admit

stay skeptical of small studies like this, friend

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paimapi

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dudisubekti  20 hours ago

> not generalizable

But there's already a general advise on this: eat more fiber.

https://med.stanford.edu/news/all-news/2017/08/hunter-gather...

We're a great ape, our body evolved to process a lot of fiber from fruits and starches. It's the modern fiber-deficient diet that's really weird.

90g/day of fiber is similar to the Hadza tribe diet, where they can consume 100-150g of fiber per day.

  • paimapi  13 hours ago

    a starch is not fiber and generally not broken down the same way in digestion afaik

    fiber is great and under-consumed (especially soluble) and is very well-studied on modern populations [0]. we don't really need to make mechanistic reasonings about evolutionary adaptations that occurred hundreds of thousands of years ago or rely on studies of a small, homogenized population whose lived realities are far from yours and mine

    plus, following the the hierarchy of evidence, mechanistic guesses are considered extremely low quality, only ranking above things like mouse studies [1]

    [0] https://www.uptodate.com/contents/healthy-diet-in-adults#H61... [1] https://en.wikipedia.org/wiki/Hierarchy_of_evidence

    • dudisubekti  12 hours ago

      Fair but resistant starch that we're speaking of behave more like soluble fiber:

      https://nutritionsource.hsph.harvard.edu/carbohydrates/fiber...

      > Resistant starch – Soluble fermentable fiber found in legumes, unripe bananas, cooked and cooled pasta, and potatoes that acts as a prebiotic. Adds bulk to stools but has minimal laxative effect. May help to normalize blood sugar and cholesterol levels.

      For stronger studies, these guys have you covered: https://www.ncbi.nlm.nih.gov/books/NBK559033/

    • adrian_b  12 hours ago

      "Fiber" is a vague term that is used for the carbohydrates that cannot be digested by humans, so they reach the large intestine, where they are fermented by bacteria.

      This includes a part of the "resistant starch", which is poorly digested by humans, so a big part of it reaches the large intestine.

      So yes, the "resistant" starch counts as "fiber", but not all of it, because some part of it is hydrolyzed into glucose, which is absorbed.

      1 reply →

  • amanaplanacanal  16 hours ago

    We shouldn't assume that because we are a great ape that we eat the same as other great apes. Humans spent two million years away from the jungle evolving in the savanna, with very different food sources. Our guts changed quite a bit in that time, and our digestion doesn't work the same.

  • iamacyborg  18 hours ago

    Fiber’s the new fad supplement.

    • preg_match  14 hours ago

      Fiber is not a supplement, or at least it’s not just a supplement. It’s the primary thing that makes fruits and vegetables healthy.

      We’ve already known fruits and vegetables are healthy. Fiber is the reason why eating an orange is good, but drinking a glass of orange juice is about equivalent to a bottle of coke. That’s not an exaggeration, by the way, it’s about the same sugar content.

      If you want to eat the recommended 35g of fiber a day, you won’t be able to reach it with just supplements. You need to be eating fruits and vegetables at every meal. For my entire life, everyone has been saying to eat fruits and vegetables at every meal in large quantities.

      1 reply →

lluisantoni  1 day ago

Also, the authors claim the starch "inhibited lipid absorption." They do not argue why they used surrogate blood biomarkers instead of residual energy output in fecal samples (which is a better measurement).

sample size is 37, number of authors 29