For example, will my opinion of Ayn Rand have to change?
To me the premise that the possibility of changing my brain through fasting is unquestionably a silver bullet free of tradeoffs is suspect. Or to put it another way, the fact that fasting had a particular effect does not imply that effect is a positive one.
Furthermore, hunger is a strong motivation toward behaviors that are ethically suspect in its absence. A full belly is a rung up Maslow’s hierarchy.
People who spend their days starving mice at scale have incentives to interpret that starvation in positive ways. It would be hard to rationalize starvation and vivisection otherwise and still consider one’s life choice reasonable and ethical. Hence, I am skeptical of acting in the ways an optimistic interpretation of the report suggests. YMMV.
Presumably neurogenesis is occurring all the time and is restricted to a small set of regions in the brain and the new neurons form in just those very strict set of regions. Those neurons are not moving to the neocortex, just a few millimeters within the dentate gyrus. That is to say even robust neurogenesis is not likely to change your mind, cognitive experience, personality or intelligence in any measurable way.
But the parent comment is unfair insofar as scientists don't randomly chose to food deprive or "vivisect" animals because they think it's intrinsically fun. Running these experiments requires a huge amount of annoying busy work that I can't imagine anyone choosing to do without being paid or having some other motive.
In particular, the reason intermittent fasting is studied is because there's a large and increasing body of research that suggests that it may be of benefit to a wide variety of health measures.
The business of cutting apart animals and looking at the insides claim revealed knowledge isn’t new. The Romans called it “haruspicy” and also built wealthy bureaucratic institutions in service of narratives useful to the powerful.
Contemporary interest in fasting research is helpful to those who find advantage in moralizing upon obesity. Intermittent fasting is a virtue reserved for those with food security. It’s attractive to people whose socio-economic status insures that going hungry is a choice and a display of will power. Not weakness. The conclusion that it makes such people smarter is self serving.
The preponderance of health evidence is that starvation is detrimental to human health and creates long term cognitive problems. But lab mice are an industrial product and labs are industrial institutions and the money keeps flowing so long as the results are acceptable to those providing it. That’s the way it has been for millennia.