Oh I don't disagree but I mean to point out that engaging in a calorie restricting diet at a young age may be detrimental to fertility, based on the effects that they suggest and the observational evidence from other animals. This may or may not be a big deal to certain people depending on goals - if you want to have children in your 20s versus 30s for example.
I think the idea is that the animals would have a better chance of surviving until food became plentiful again, at which point their intake would return to normal along with fertility and aging.