I think the implication is that you age slower if you consume fewer calories. So if you adopt CR then you might feel at age 50 how someone on a normal diet feels at age 40, and at 100 you might feel as they do at 80.
When I want to lose fat I go low calorie high protein (below 2000kcal). I get constant food cravings and I can't even get myself to do anything in the gym, also have a hard time focusing at work. It was considerably better when I wasn't lifting - then you get used to it (I still felt weak) - but weight training + low calorie = very draining.
But 2000kcal is already well below a male doing normal things during the day; so 2000 + gym with weights would drop that completely out. When I do weights I try to shoot for around 2500 which already sucks compared to what I was used to (which does affect performance but it feels the same so I think overall I benefit?). But when just doing cardio I can go well below 2000 on a day or just not eat at all (only tea + water) and feel sharp, I just choose not to and just do days without any food.
I cannot imagine doing every day below 2000 and then going to the gym indeed. That would definitely not be productive and painful, but doing days of weights with 2500 max, other days around 2000 and then some days 0 works fine for me.
Yea going really low calories and working out is really nasty - you visibly start shaking during practice and start feeling really strange - I'm guessing from lack of blood sugar. Will not be doing that in the future.
I'm trying something along those lines this month - I eat maintenance calories and work out over the week (~3000) and then I eat ~1000 on the weekend (mostly from coffe/milk/protein shake), but I want to do side projects on the weekend - sometimes I can get in the zone and food doesn't even get on my mind, other times I just feel like doing nothing when I haven't eaten.
No, the suck factor is greater when you're old as opposed to when you're younger, that is unless you live about the same way all your life. Imagine how a professional athlete feels.
Additionally, why is a restricted diet healthy if it lowers one's definition of quality of life? I read a study somewhere that showed that castration helps men live longer. Not my definition of healthy.
Maybe because people who are young and never had anything wrong with them want to (and think) they will live forever? So they don't like your negativity possibly. Just guessing here, but this drive to 'live forever' seems mostly advocated by people young people; once you (or a loved one) had a roll of the dice (something you could not have prevented with your fasting, weight lifting, sports etc), however small, you will change your mind; it is now, not in the future you need to enjoy.
Although living healthy works in ways, shit happens and then growing old indeed sucks. And it is not only your health; my grandparents both died within a year of each other, healthy as oxes with brains fully intact (both their hearts stopped in their sleep), still living together at 95 years old. They were lucky we think but they didn't consider that always; all their friends and relatives were dead. For a long time most of them. Their brothers and sisters; dead. Everything they had done in their lives; forgotten and dead besides their children. Of course that gave them joy together with grandchildren but still, the days were long and lonely for them even while they still had each other.