[hollerith]

> Our evolutionary ancestors never had need to evolve means to process much of it.

That's not true because about half of the carbs in fruits and vegetables is fructose. (Cherries have the lowest ratio I know about at about 30%; apples and pears have the highest at around 70%; most fruits and vegetable are almost exactly half fructose and half glucose.)

Also, if you eat a spaghetti meal or a lot of potatoes (which rapidly become glucose and get absorbed) your body will convert a decent amount of the glucose into fructose according to researcher Robert Lustig MD.

(I don't disagree with your overall point that most affluent people consume too much fructose. In the ancestral environment however calories were scarce enough that people should have and did eat almost all the fructose they could find.)

[loeg]

Worth keeping in mind that Lustig is a crank who says a lot of things that are beyond what is supported by the science and most likely untrue. I don't know if that particular statement is true or not, but I am less likely to believe it with Lustig's name attached than without it.

[angiosperm]

Prehistorically, fructose without intermixed fiber was found mainly in honeycombs, i.e. rarely. Beverages are the way most people get the most concentrated blasts of fructose nowadays. With enough fiber, intestinal bacteria get first crack at it. (Keep your intestinal bacteria well-fed; hungry bacteria will eat you instead.)

Your body has processes to produce fructose, which is then processed by the liver to fat for storage, when preparing for lean times seems indicated.

It is hard to research, but it seems like mangoes have the highest proportion of fructose. Honey has more fructose than glucose, and agave syrup is mostly fructose.