Stephan of Whole Health Source had a run-in at AHS with Gary Taubes, who cited the Pima Indians as an example of the evils of carbohydrates in criticizing Stephan's Food Reward Theory. As Stephan notes, he replied that the example of the Pima actually supports his Food Reward Theory as the Pima transitioned from beans to refined flour. And here we start to see a problem with examining the Food Reward Theory (FRT).
To show that something is an example of FRT in action, you need to show (1) that the amount of food consumed has risen* and, more importantly, (2) that the rise in consumption is a result of changes in brain chemistry. Without at least these two components, you cannot give any person or population as an example of FRT.
Since preference for tastey food is conceptually tautological and, practically, would seem a given outside taboo practices, and since access to tastey food [=subset of all food] is greater in modern societies, it is almost a given that the transition to or contact with modern societies will result in a preference for consumption of tastey foods. However, this observation is different from the question of why people would choose to overconsume in modern societies**. So, searching for examples of FRT puts you in constant danger of falling prey to the correlation-causation fallacy by the very nature of the problem. The fact that FRT seems to put a "scientific" veneer on the "evil modern society" paradigm of many Paleo people only means that people with that paradigm are in constant danger of bias.
Whether Taubes is wrong about the Pima is irrelevant. Theoretically, sugar could be causing body fat gain via Taubes' paradigm and causing increased overconsumption via Guyenet's paradigm. The two are not mutually exclusive. My only point here is to remind us that FRT requires evidence of brain changes. Even if you were to do an interventional study with bland foods vs. tastey foods, it could not be used as evidence of FRT without showing that, in such a study, brain changes between the study and control groups occurred.
* Or, (1b) that, if not more, the food consumption is directly responsible for a decline in activity level thermodynamically equivalent to an increase in caloric consumption. It should be remembered that FRT relies on traditional calorie-counting
** Vis-a-vis their body fat and disease: whether someone overconsumes in an absolute sense or only in relation to certain macronutrients is another question.