Glucose in blood is one of the sources of energy, not the sugar itself. Is it primary source of energy? I don't think so, because of successful application of ketogenic diets.
A person weighting 100kg should have less than 10 (ten) grams of sugar in a blood. This is less than 40 calories circulating in the blood of this 100kg person. The same person should have less than 10 (ten) grams of ketones in the blood and it is equivalent to less than 90 calories cirrculating.
Ketones are much more efficient energy source, they are twice as energy-dense. Glucose use needs a quarter of energy stored in the glucose, while fat (ketones) need only 3 (three) percents. Glucose needs insulin, fat (ketones) does not.
Glucose (which is not even table sugar!) is not a main source of energy in the body.
I also think that "variety" is a fad, just like other "extremes" you mentioned.
A person weighting 100kg should have less than 10 (ten) grams of sugar in a blood. This is less than 40 calories circulating in the blood of this 100kg person. The same person should have less than 10 (ten) grams of ketones in the blood and it is equivalent to less than 90 calories cirrculating.
Ketones are much more efficient energy source, they are twice as energy-dense. Glucose use needs a quarter of energy stored in the glucose, while fat (ketones) need only 3 (three) percents. Glucose needs insulin, fat (ketones) does not.
Glucose (which is not even table sugar!) is not a main source of energy in the body.
I also think that "variety" is a fad, just like other "extremes" you mentioned.