How do humans meet the brain’s glucose demand of 420kcal (105g sugar) per day on a healthy diet? Wouldn't the protein demand in case of gluconeogenesis be tremendous?


  • Can you please cite your source?
    – Remi.b
    Mar 29, 2018 at 3:07
  • Oups, my bad. ncbi.nlm.nih.gov/books/NBK22436
    – NeoGenAalem
    Mar 29, 2018 at 4:23
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    It would be better to remove the personal health side of things and just talk about supplying the brain with energy in the context of diets that don't directly provide the necessary amount of glucose or immediate precursors.
    – Bryan Krause
    Mar 29, 2018 at 5:03
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    @NeoGenAalem, gluconeogenesis is not only from proteins but also from lactate and fats as stated in the article you linked to: "The main precursors for gluconeogenesis are lactate and alanine from muscle, glycerol from adipose tissue, and glucogenic amino acids from the diet.
    – Jan
    May 3, 2018 at 6:22

1 Answer 1


Most of your diet is carbohydrates, which are or can be directly converted into sugars, Vegetables, fruits, and grains are all primarily carbohydrates. Unless you are eating a exclusively animal based diet getting glucose for the brain is not difficult.

Contrary to what fad diets claim a healthy diet contains a lot of carbohydrates. What is unhealthy is when your diet contains only refined pure carbohydrates and not the vitamins fiber and other nutrients.

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