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There are costs to gluconeogenesis (glucose via protein catabolism), kidney issues to name one (deamination producing ammonia). The body does not synthesize glu

There are costs to gluconeogenesis (glucose via protein catabolism), kidney issues to name one (deamination producing ammonia). The body does not synthesize glucose from fatty acids (beta-oxidation occurs producing aceytl-coA in the mitochondria, thus producing energy, but aceytl-CoA cannot be converted upwards in the pathway to glucose). A small amount of glucose can/does get created from glycerol. Nutrition recommendations up to this point still recommend high ratio of carbs (45-65% of kcals) because they are the most direct metabolic pathway. Also incredibly important for gut health is fiber, which is a complex carbohydrate (and prebiotic). The concern of carbs is non-complex ones as a high percentage of intake. They have found that the brain runs on ketones (for a long time it was thought that it required glucose specifically) but long term research is non-existent. So yes, the body can live off of "no carbs", but stating that our carbohydrate requirement is zero is just false according to the literature and nutritional history of the majority of humans.

lucisferre 10y ago
So you're saying HN comments are not a good source of my daily nutritional information?
- calvano915 10y ago
  :) Like everything else in life, nutrition as a science is incredibly more complicated than we want to believe or describe. A seriously good place to start is MyPlate (their nutrition AND physical activity recommendations).
overgard 10y ago
I'm always skeptical when I hear "Nutrition recommendations" because it implies some sort of authority. Nutrition recommendations from who? The USDA? It's worth reading the history of the food pyramid. Here's a quote from wikipedia: "The first chart suggested to the USDA by nutritional experts in 1992 featured fruits and vegetables as the biggest group, not breads. This chart was overturned at the hand of special interests in the grain, meat, and dairy industries, all of which are heavily subsidized by the USDA.[10] If Americans followed the chart suggested, they would buy much less meat, milk, and bread. On the other hand, if they ate as the revised chart suggested, it "could lead to an epidemic of obesity and diabetes," as original composer of the food Pyramid, Louise Light warned. " I know from a personal standpoint, once I removed refined carbohydrates from my diet I dropped 25 pounds in two months (without bothering to excersize.) So the idea that somehow the diet that made me fat is somehow the "good" diet because the USDA says so strikes me as being silly.
- calvano915 10y ago
  Skepticism is important for any advice. MyPlate/USDA dietary guidelines are updated often, based on all the research and debunking that has happened before and since 1992. As I mentioned in another comment, it's a good place to start for most people. There is going to be some influences affecting their recommendations but most people can benefit from the overall approach. A diet with high carbs should be mostly complex carbs. There is no minimum refined carb recommendation. The only recommendation is to limit added sugars to <10% of daily kcals. That recommendation may be reduced further in later revisions.
  - overgard 10y ago
    I think we both agree that complex carbs are better than refined ones, and there are foods that are somewhat heavy in carbohydrates that are still good for you (kale, for instance). I'm super skeptical that 45-65% of diet being carbohydrates is healthy though. Unlike proteins and fats carbohydrates don't have much nutritional value other than being useful for creating glucose. Since your body can synthesize glucose anyway, you don't really need that much. In terms of fiber, you can get that from vegetables. I don't necessarily think you have to cut out carbs completely and go on ketosis, but of all the major macronutrients carbs are the least useful, so it seems odd that they should be the vast majority of the diet, especially when we've known for at least a hundred years that carbohydrates are fattening. (I'm amused when people act like ketogenic diets are "new" -- historically high fat/low carb diets were common. And historically we didn't have an obesity problem.)
    - PepeGomez 10y ago
      "the body can synthesize glucose" is a horribly misleading statement. The body can create glucose only by destroying protein and the amount it can create is limited by the buildup of toxic waste the process leaves behind. It's absolutely not the same thing as the body synthesizing vitamin A from carotene. You will be much better off eating carbohydrates, and 45% may be still too little.
      - 10y ago

lucisferre 10y ago

So you're saying HN comments are not a good source of my daily nutritional information?

calvano915 10y ago
:) Like everything else in life, nutrition as a science is incredibly more complicated than we want to believe or describe. A seriously good place to start is MyPlate (their nutrition AND physical activity recommendations).

overgard 10y ago

I'm always skeptical when I hear "Nutrition recommendations" because it implies some sort of authority. Nutrition recommendations from who? The USDA? It's worth reading the history of the food pyramid. Here's a quote from wikipedia: "The first chart suggested to the USDA by nutritional experts in 1992 featured fruits and vegetables as the biggest group, not breads. This chart was overturned at the hand of special interests in the grain, meat, and dairy industries, all of which are heavily subsidized by the USDA.[10] If Americans followed the chart suggested, they would buy much less meat, milk, and bread. On the other hand, if they ate as the revised chart suggested, it "could lead to an epidemic of obesity and diabetes," as original composer of the food Pyramid, Louise Light warned. " I know from a personal standpoint, once I removed refined carbohydrates from my diet I dropped 25 pounds in two months (without bothering to excersize.) So the idea that somehow the diet that made me fat is somehow the "good" diet because the USDA says so strikes me as being silly.

calvano915 10y ago
Skepticism is important for any advice. MyPlate/USDA dietary guidelines are updated often, based on all the research and debunking that has happened before and since 1992. As I mentioned in another comment, it's a good place to start for most people. There is going to be some influences affecting their recommendations but most people can benefit from the overall approach. A diet with high carbs should be mostly complex carbs. There is no minimum refined carb recommendation. The only recommendation is to limit added sugars to <10% of daily kcals. That recommendation may be reduced further in later revisions.
- overgard 10y ago
  I think we both agree that complex carbs are better than refined ones, and there are foods that are somewhat heavy in carbohydrates that are still good for you (kale, for instance). I'm super skeptical that 45-65% of diet being carbohydrates is healthy though. Unlike proteins and fats carbohydrates don't have much nutritional value other than being useful for creating glucose. Since your body can synthesize glucose anyway, you don't really need that much. In terms of fiber, you can get that from vegetables. I don't necessarily think you have to cut out carbs completely and go on ketosis, but of all the major macronutrients carbs are the least useful, so it seems odd that they should be the vast majority of the diet, especially when we've known for at least a hundred years that carbohydrates are fattening. (I'm amused when people act like ketogenic diets are "new" -- historically high fat/low carb diets were common. And historically we didn't have an obesity problem.)
  - PepeGomez 10y ago
    "the body can synthesize glucose" is a horribly misleading statement. The body can create glucose only by destroying protein and the amount it can create is limited by the buildup of toxic waste the process leaves behind. It's absolutely not the same thing as the body synthesizing vitamin A from carotene. You will be much better off eating carbohydrates, and 45% may be still too little.
    - 10y ago