jayboknows t1_j7zngdw wrote
Reply to comment by MushroomNovaCat in Effect of long-term caloric restriction on DNA methylation measures of biological aging in healthy adults from the CALERIE trial (Feb 2023) by basmwklz
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As the authors noted, this can be seen in multiple species. In animal trials, caloric intake is often achieved by manipulating quantity of food, not type. This could suggest that energy would independently impact longevity, and that it's not simply a matter of eliminating highly processed foods. While animal studies are not the highest degree of evidence, they are often useful for determining mechanisms of action when confounding variables like this can be accounted for. This is not to say that diet quality does not also have an independent or synergistic effect on longevity, but it would point toward energy intake being a piece of the puzzle, at least.
MushroomNovaCat t1_j80fvzg wrote
Not necessarily, the reason being that animals are fed more fiber to keep them from being hungry in these studies and we already know that fiber is beneficial to health.
jayboknows t1_j80hz8h wrote
Diet composition compared to energy intake has also been investigated in animals. Read the introduction to the linked study and the authors discuss previous findings demonstrating CR working independently from diet composition.
“We recently completed a longitudinal study in male C57BL/6J mice (B6) initiated at 4 months of age in which the effects of the two diet compositions under ad libitum (AL) and CR conditions were measured (Mitchell et al., 2019). Independent of diet, male B6 mice on 30% CR exhibited significant improvements in health, survival, and a delayed onset of cancer with respect to AL-fed mice.”
https://www.sciencedirect.com/science/article/pii/S1550413120302357
MushroomNovaCat t1_j80ncwf wrote
I don't see any diet specifics listed. As I said, fiber is given to animals to account for the missing calories in these studies and we already know that fiber has beneficial effects on health, as was pointed out by this study.
MushroomNovaCat t1_j80o8cy wrote
I'll also add that we don't see the mood and cognitive effects of caloric restriction monitored in these studies. We already have several studies demonstrating that "hangryness" is real and has negative effects on mood and cognition which once again, circles back to my original comment. Just because we can recognize the benefits of certain practices even if we don't precisely understand them doesn't mean that those practices are sustainable or that they don't affect other areas negatively.
jayboknows t1_j81dmi6 wrote
I do not dispute that fiber has health promoting benefits. I do feel that it’s a bit of a straw man from the original point, though. The discussion seemed to be that the less processed food, in the blue zones, was responsible for increases in longevity, independent from CI. From that perspective, I believe the animal studies, where diet composition is the same (degree of processing isn’t different) and CI is the IV, are useful. I believe they provide evidence that energy intake affects longevity independent processed food consumption.
MushroomNovaCat t1_j81f8rp wrote
It's not a straw man, my point was that diet is not monitored in most of these studies as was noted in the study you linked and even when diet is monitored, it is still not equal because fiber is used to supplement the diets of the animals eating the calorie restricted diet, therefore the diets are not equal in nutritional value. There's more to a good diet than low amounts of highly processed foods as I noted in a different comment, a low amount of consumed animal products along with a good amount of fiber and adequate consumption of all essential amino acids, proteins, fats, carbs, vitamins and minerals is also needed.
There has not been a study that has established why caloric restriction results in increased health and longevity therefore we can't say that it's not the co-factors associated with caloric restriction (i.e., better diets, intermittent fasting, fasting correlated with circadian rhythms, etc.) that are primarily responsible for the beneficial effects rather than the restriction of calories itself.
My purpose in pointing out blue zone diets was to demonstrate that health and longevity do not require caloric restriction. My point was also to demonstrate that caloric restriction leads to hunger and hunger leads to impaired mood and cognition which has also been well documented in other studies. Caloric restriction has benefits but we can reap those benefits through a good diet, without restricting calories, without going hungry, and without affecting our mood and cognitive abilities.
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