4 ms·

> Why do humans, pets, and even lab animals of many species kept in controlled lab conditions on standardized diets appear to be increasingly obese over the 20t

> Why do humans, pets, and even lab animals of many species kept in controlled lab conditions on standardized diets appear to be increasingly obese over the 20th century? What could possibly explain all of them simultaneously becoming obese? Because diet is only part of the equation. The other major factor being exercise/physical activity (and probably some genetics). If you eat 'well' but sit at a desk all day, calories in != calories out and you'll probably gain weight. Also, since this doesn't cite any sources for the conclusion presented here as a question, do we know that the 'conditions' were held constant? (hint: no, probably not)

jhallenworld 8y ago
My pet theory (at least for humans) is that this is due to better dental care.
- hammock 8y ago
  Care to elaborate?
  - jhallenworld 8y ago
    Oral hygiene has been improving over time, see: https://fluoridefree.org.nz/fuoridation-status-countries/countries-fluoridation-graph/ https://fluoridefree.org.nz/fuoridation-status-countries/cou... Perhaps people with the bad oral hygiene of the past had a different gut biome, had more stomach infections, or just had less pain when eating and this led to less calorie absorption.
    - hammock 8y ago
      It's not obvious to me how more cavities leads to less calorie absorption - this is your pet theory can you explain it? In regard to gut biome and stomach infections, there is a lot of evidence that fluoride actively destroys your gut - disturbing the microbiome, breaking down the gut barrier and promoting inflammation - so I'm not sure that part holds water.
hyperpallium 8y ago
That doesn't cover lab animals. I've also read that animals in the wild also weigh more. One explanation is higher global CO_2 levels, giving faster growth, which means more calories (and fewer other components). So, the same amounts of food now have more calories. There's also arguments for hormones in the general food supply. Possible global factors are pollution in general, and plastics in particular. (For wild animals, decrease in biodiversity may be a factor).
- deleted 8y ago
  [deleted]
gnulinux 8y ago
I personally believe carbs are mostly to blame (as opposed to fats and protein). In the Western world there is this idea that fats are bad, carbs are good but somehow this idea coincidences with astronomic increase in obesity. We load everything with high-fructose corn syrup and kick fats out of our diet. There is not much research behind this and my claims aren't evidence based either. I'm more than happy to refuted if you can provide papers.
- glastra 8y ago
  Definitely. I don't understand why you're getting down-voted without actual refutals. I guess it generates some internal/psychological discomfort, but I expected better of HN readers. Indeed, the only animals suffering from obesity and modern civilisation diseases (diabetes, cardiovascular disease, Alzheimer's and other degenerative or systemic diseases) are humans and those animals of other species unfortunate enough to be fed by humans. Diet composition is obviously to blame, but not just carbohydrates (be them complex or simple, refined or "natural"). Omega-6 polyunsaturated fatty acids (and especially their ratio to omega-3's) in the diet lead to inflammatory responses throughout the body, which can, and do, wreak havoc on health. If you look at trends in modern nutrition, carbohydrate and omega-6 consumption are at their highest and have sky-rocketed in the past 60-70 years, as have rates of prevalence for various diseases. Of course, correlation is not causation, but many studies are coming out in the recent years showing the mechanisms through which all of this takes place.
  - gnulinux 8y ago
    This might be true but is very surprising (since Omega 6 polyunsaturated fatty acids are found poultry, eggs, nuts etc... which I thought to be rather "healthy" in general) I found this [1] abstract which supports your point. Is there more evidence? Also what's the relation between inflammation and obesity? [1]: https://www.ncbi.nlm.nih.gov/pubmed/29610056 https://www.ncbi.nlm.nih.gov/pubmed/29610056
    - glastra 8y ago
      The amount of omega-6 PUFAs in eggs is almost negligible compared to MUFAs and SFAs [1, table 1]. Assuming that a single egg yolk is around 20 grams, that's less than 1 gram of omega-6 per egg. One would have to eat an absurd amount of eggs daily (think >50) for it to matter. Some nuts and seeds do contain high amounts of omega-6. Sunflower seeds and peanuts especially. That is why non-high-oleic sunflower oil is so bad for health. Almonds, hazelnuts, macadamias and others have much better fatty acid profiles. In general, all industrially extracted vegetable oils are rich in pro-inflammatory omega-6 fatty acids. Replacing them with animal fats or cold-pressed vegetable oils (olive, avocado or coconut, all of them relatively low in omega-6) is a very easy dietary intervention that should have a profound effect on health, similar to cutting sugars. Here is a non-comprehensive list of studies and articles if you want to dig a bit deeper: - https://openheart.bmj.com/content/1/1/e000032 https://openheart.bmj.com/content/1/1/e000032 - https://www.hindawi.com/journals/jnme/2012/539426/ https://www.hindawi.com/journals/jnme/2012/539426/ - https://www.sciencedirect.com/science/article/abs/pii/S1098882316300363 https://www.sciencedirect.com/science/article/abs/pii/S10988... - https://openheart.bmj.com/content/openhrt/5/2/e000898.full.pdf https://openheart.bmj.com/content/openhrt/5/2/e000898.full.p... - https://breaknutrition.com/omega-6-fatty-acids-alternative-hypothesis-diseases-civilization/ https://breaknutrition.com/omega-6-fatty-acids-alternative-h... - https://www.physiology.org/doi/pdf/10.1152/ajpheart.00480.2004 https://www.physiology.org/doi/pdf/10.1152/ajpheart.00480.20... (especially interesting as it points to a possible synergy of omega-6 fatty acids and carbohydrates) I hope that helps. [1]: https://academic.oup.com/ps/article-pdf/79/8/1168/8203403/poultrysci79-1168.pdf https://academic.oup.com/ps/article-pdf/79/8/1168/8203403/po...
hazz99 8y ago
> If you eat 'well' but sit at a desk all day, calories in != calories out and you'll probably gain weight. How can this be true? Energy cannot be created - it has to come from somewhere.
- thecatspaw 8y ago
  they are saying that gaining weight is by taking in more calories than spending them, and that sitting all day lowers the calories out
  - hazz99 8y ago
    Ah, I misunderstood. Cheers!

jhallenworld 8y ago

My pet theory (at least for humans) is that this is due to better dental care.

hammock 8y ago
Care to elaborate?
- jhallenworld 8y ago
  Oral hygiene has been improving over time, see: https://fluoridefree.org.nz/fuoridation-status-countries/countries-fluoridation-graph/ https://fluoridefree.org.nz/fuoridation-status-countries/cou... Perhaps people with the bad oral hygiene of the past had a different gut biome, had more stomach infections, or just had less pain when eating and this led to less calorie absorption.
  - hammock 8y ago
    It's not obvious to me how more cavities leads to less calorie absorption - this is your pet theory can you explain it? In regard to gut biome and stomach infections, there is a lot of evidence that fluoride actively destroys your gut - disturbing the microbiome, breaking down the gut barrier and promoting inflammation - so I'm not sure that part holds water.

hyperpallium 8y ago

That doesn't cover lab animals. I've also read that animals in the wild also weigh more. One explanation is higher global CO_2 levels, giving faster growth, which means more calories (and fewer other components). So, the same amounts of food now have more calories. There's also arguments for hormones in the general food supply. Possible global factors are pollution in general, and plastics in particular. (For wild animals, decrease in biodiversity may be a factor).

deleted 8y ago
[deleted]

gnulinux 8y ago

I personally believe carbs are mostly to blame (as opposed to fats and protein). In the Western world there is this idea that fats are bad, carbs are good but somehow this idea coincidences with astronomic increase in obesity. We load everything with high-fructose corn syrup and kick fats out of our diet. There is not much research behind this and my claims aren't evidence based either. I'm more than happy to refuted if you can provide papers.

glastra 8y ago
Definitely. I don't understand why you're getting down-voted without actual refutals. I guess it generates some internal/psychological discomfort, but I expected better of HN readers. Indeed, the only animals suffering from obesity and modern civilisation diseases (diabetes, cardiovascular disease, Alzheimer's and other degenerative or systemic diseases) are humans and those animals of other species unfortunate enough to be fed by humans. Diet composition is obviously to blame, but not just carbohydrates (be them complex or simple, refined or "natural"). Omega-6 polyunsaturated fatty acids (and especially their ratio to omega-3's) in the diet lead to inflammatory responses throughout the body, which can, and do, wreak havoc on health. If you look at trends in modern nutrition, carbohydrate and omega-6 consumption are at their highest and have sky-rocketed in the past 60-70 years, as have rates of prevalence for various diseases. Of course, correlation is not causation, but many studies are coming out in the recent years showing the mechanisms through which all of this takes place.
- gnulinux 8y ago
  This might be true but is very surprising (since Omega 6 polyunsaturated fatty acids are found poultry, eggs, nuts etc... which I thought to be rather "healthy" in general) I found this [1] abstract which supports your point. Is there more evidence? Also what's the relation between inflammation and obesity? [1]: https://www.ncbi.nlm.nih.gov/pubmed/29610056 https://www.ncbi.nlm.nih.gov/pubmed/29610056
  - glastra 8y ago
    The amount of omega-6 PUFAs in eggs is almost negligible compared to MUFAs and SFAs [1, table 1]. Assuming that a single egg yolk is around 20 grams, that's less than 1 gram of omega-6 per egg. One would have to eat an absurd amount of eggs daily (think >50) for it to matter. Some nuts and seeds do contain high amounts of omega-6. Sunflower seeds and peanuts especially. That is why non-high-oleic sunflower oil is so bad for health. Almonds, hazelnuts, macadamias and others have much better fatty acid profiles. In general, all industrially extracted vegetable oils are rich in pro-inflammatory omega-6 fatty acids. Replacing them with animal fats or cold-pressed vegetable oils (olive, avocado or coconut, all of them relatively low in omega-6) is a very easy dietary intervention that should have a profound effect on health, similar to cutting sugars. Here is a non-comprehensive list of studies and articles if you want to dig a bit deeper: - https://openheart.bmj.com/content/1/1/e000032 https://openheart.bmj.com/content/1/1/e000032 - https://www.hindawi.com/journals/jnme/2012/539426/ https://www.hindawi.com/journals/jnme/2012/539426/ - https://www.sciencedirect.com/science/article/abs/pii/S1098882316300363 https://www.sciencedirect.com/science/article/abs/pii/S10988... - https://openheart.bmj.com/content/openhrt/5/2/e000898.full.pdf https://openheart.bmj.com/content/openhrt/5/2/e000898.full.p... - https://breaknutrition.com/omega-6-fatty-acids-alternative-hypothesis-diseases-civilization/ https://breaknutrition.com/omega-6-fatty-acids-alternative-h... - https://www.physiology.org/doi/pdf/10.1152/ajpheart.00480.2004 https://www.physiology.org/doi/pdf/10.1152/ajpheart.00480.20... (especially interesting as it points to a possible synergy of omega-6 fatty acids and carbohydrates) I hope that helps. [1]: https://academic.oup.com/ps/article-pdf/79/8/1168/8203403/poultrysci79-1168.pdf https://academic.oup.com/ps/article-pdf/79/8/1168/8203403/po...

hazz99 8y ago

> If you eat 'well' but sit at a desk all day, calories in != calories out and you'll probably gain weight. How can this be true? Energy cannot be created - it has to come from somewhere.

thecatspaw 8y ago
they are saying that gaining weight is by taking in more calories than spending them, and that sitting all day lowers the calories out
- hazz99 8y ago
  Ah, I misunderstood. Cheers!