It would be interesting to hear both why the chose a "high fat-high sugar" diet and to see further research that did more isolated tests in the vein of "high carb", "high fat" and "high protein" instead of combinations of them. Also, what are the implications of altered gut makeup after adopting these diets? Surely we could come up with experiments to measure metabolism and behavior as a result of the altered gut bacteria.
It will be fascinating to see how our understanding of nutrition and diet changes as science finally catches up. Studies like this are just the beginning.
It does seem like a very simple study, that we would have guessed the results. Seems like a study like this would be to help facilitate laws or actions rather than finding the really important answers you are suggesting. I hope one day we come up with a model to fund research for the people, and not wait for larger organizations to fund, typically for selfish reasons. I think if we could find this model science will not only catch up, but trail-blaze new findings.
It will be fascinating to see how our understanding of nutrition and diet changes as science finally catches up. Studies like this are just the beginning.