I watched this last night, and it aggravated me a bit because she didn't talk about diet at all:
Cynthia Kenyon on experiments that hint of longer lives
So, if you watch that, you'll see that there is this relationship between insulin, IGF-1 and ageing.
The upshot being, if you don't want to age, you probably don't want to eat whey.
The other side of the coin- do you want to gain some muscle? Whey protein seems to help a lot with gaining muscle. It would likely be easier to keep the muscle, once you gain it, while dropping whey. Milk is for growing; meat is for maintaining? One could theoretically turn on the growth for a few weeks, and then spend the rest of the year in an age defying mode.
The video left me thinking maybe I should read Nora Gedgaudas' book, because if I remember her AHS talk correctly, she's not only mentioned low-carb, but less protein, which is exactly what Cynthia Kenyon would have talked about if she wasn't funded by drug pushers.