In modern philosophy of the mind an unresolved issue is the question of qualia [update: I might be wrong about this actually]. What is 'whiteness' or 'sweetness,' as such? Well, I'm not a philosopher, but one thing that has interested me over the past few years has been the genetics of taste. Not surprisingly there seems to be a strong genetic and biological component in regards to perception and preferences. For example, it has long been known that there is variation in the extent of sensitivity to "bitter," assayed via the famous PTC test. Of late it has been shown that not only are there two phenotypic variants, rather, there are three, "non-tasters," "tasters" and "super-tasters," inherited in a simple Mendelian fashion. "Non-tasters" must inherit two copies of the loss of function allele to manifest, while "super-tasters" must inherit two functional alleles, while "tasters" carry one of each, so there is additivity on this locus (Since the two taste sensitive groups were once lumped together it had previously been thought there was a dominance-recessive relationship). This has important life history ramifications, believe it or not, and the variant which you carry helps predict your inclination toward eating vegetables (those with strong sensitivity to bitter tastes are more vegetable averse). Now comes word that people who like sweets eat more fruit. Your first thought might be "they did a study on this?" I know, I know. But, for me the key is to find out whether there is heritable or genetically encoded variation on this trait, because that has evolutionary significance. It seems that our propensity toward foods would be strongly selected for as it would impact upon our reproductive success. We are used to thinking of 'frugivores' and 'follivores' (fruit & vegetable lovers, respectively) in the context of interspecies difference, but, it seems highly plausible that within our own species there is a wide variation in 'natural' preference of diet. In practical terms this means the end of one-size-fits-all dieting rules. Related:Why Some Like it Hot.