For the ~2M years we came into form, glacial periods lasted longer than interglacial, so fructose was pretty rare. Modern people who visit the jungle think that fruit is everywhere, it isn’t. The fruit that is there is usually from a human who more recently cultivated it there. 100k+ years ago, no fruit tree farms, certainly not in Eurasia until very very recently.

I think the berries they’d stuff their faces with maybe once a year probably did do some damage to their livers, but 1. The liver is extremely resilient and regenerative and 2. Minor liver damage would basically never be a cause of death and wouldn’t play even a marginal role in evolutionary fitness.

If you’re otherwise metabolically healthy, exercise ideally daily, and have good body composition, you’re probably fine with say *tens* of grams of fructose a day. But I don’t see any scenario where *hundreds* of grams daily doesn’t cause meaningful damage, no matter the source or additional fruit molecules.