Fructose can be obtained and/or generated from the diet (sugar, HFCS, high glycaemic carbs, salty foods, umami foods, alcohol) as well as under conditions of stress (ischaemia, hypoxia and dehydration). Indeed, the three attractive tastes (sweet, salt, umami) all encourage intake of foods that generate fructose [7,10,12,19], while the bitter and sour tastes likely were developed to avoid foods that might carry toxins.
R. J. Johnson et al., “The fructose survival hypothesis for obesity,” Philosophical Transactions of the Royal Society B: Biological Sciences, vol. 378, no. 1885, Sep. 2023.