It all sounds like individual preferences with coffee and sweeteners are in such a way that they promote the individual's health by trying to combat the body's own naturally higher risk of obesity based on genetic differences.  Like if I am prone to being obese and I am also one who has a dysfunctional reward pathway that doesn't sense reward/pleasure very well, it may be helpful for me to naturally gravitate to sweetened drinks and beverages to enhance this pathway and thus help combat the negative aspect of my FTO gene increasing my odds of obesity.  It seems as though this "preference" essentially is an instinctive or perhaps pre-programmed drive to maintain a healthy body weight, or at the very least, just to try to mitigate the issues of the FTO gene.  Thoughts?