I don't think it has been debunked. Most people who are able to maintain CR for long periods of time (years or decades), seem to be mostly very healthy and have better aging biomarkers. Reason has speculated that you could gain a few years of life through CR but the gains will probably not be as dramatic as those seen in short-lived mammals or simpler life forms. The key point is that CR does not "rejuvenate" it only slows down the aging process.
It's true that CR does not rejuvenate, but long-term fasting does (during the refeeding stage, which is absent in the sustained CR). The rejuvenating effect is startling and lasting for people under 55 but less so for older folks and is transient in those over 60+.
My impression is that popularity if the original form of CR has been supplanted by various forms of fasting, from time restricted feeding to intermittent fasting. I think all these forms lead to a diminished total calorie intake, if counted, say, monthly, or, in case of long-term fasting, for a whole year. I also think this is more natural, in the sense that, in nature, times of plenty and scarcity intersperse and are reflected in the feeding patterns.
Also, it was extensively discussed years ago, in several threads, that CR'd mice, due to their super-fast metabolism, end up fasting; i.e. they finish their portion in a couple of hours, and end up fasting proper-- including going into ketosis! -- until their next meal. This was definitely true when they were fed once a day, and I think it was also true, to an extent, when they were fed twice a day. This meant that they had a refeeding stage. It's too bad that the differences in metabolic rate are seldom mentioned.
But hey, whatever works for you. I may be biased in this regard since my introduction to CR was through long-term fasting. Like many people who tried it both ways, I find it easier not to eat at all, for a stretch, than continuously struggle with hunger.
Edited by xEva, 17 February 2019 - 09:14 PM.