I have a wild theory about longevity. For all the mammals, increased heart rate correlates with lower life span [0]. But heart rate itself may just be a measurement, and what's important is rate of metabolism - higher metabolism, higher heart rate, lower life span. And vice versa.
If we very boldly assume these relationships are causal and predictive to individuals, it follows lower energy consumption -> longer life. Caloric restriction might be one way to do this.
However, with lower metabolism, stuff in the body tend to get older. This will make them fail more easily, then you are likely to get sick, which will shorten your life. Therefore the optimal strategy to maximum life expectancy seems to be control metabolism (by exercise / calory intake etc.) to a certain point where you are just unlikely to get sick, then stop.
These correlations probably have more to do with the membrane pacemaker view of resistance to oxidative damage, and how lipid composition of membranes varies with metabolic demands. Look at birds and bats, for example: tiny, with rapid heart rates, and very long lived in comparison to other species of similar size.
Heart rate is genetic - some people like me and my family have increased resting heart rate even while being athletic (one cousin was a table tennis champ and other highly competitive swimmer, both have increased resting rate). And our genes make us look young (20-30s) even in our 50s, as I can see on my relatives. So different genotypes have different characteristics I guess.
I have thought about this too and while I think it is a good starting point, there are many variables you may not have thought of, such as is it about heart rate on average or perhaps more about actual number of heart beats in a lifespan (eg, short high-intensity workouts vs distance running? Drugs that increase heart rate being used daily, etc)
I honestly think it might not be about caloric intake itself, but the content of those calories. Papers like this:
Make me wonder what the effect of certain foods might be on telomere and mitochondria. In the same way it has been shown that charred or overcooked meats (red meats in particular) can have certain adverse long term effects, it makes me wonder if certain chemicals or cooking methods contribute to reduction of effenciency in cells mitocondria or can cause dna damage that results in shorter life spans.
In this case, the increase in caloric consumption might just be that with more calories in, the more likely some of those calories are to be ones that might damage some tissue functionality somehow, and it's the actual calories to life expectancy is more of a correlation and less of a causation.
Here is a paper that showed "For every 1 serving/d greater intake of processed meat, the T/S ratio was 0.07 smaller".
On your note though, I would say everything we have talked about indicates that one particular combo would seem to be an ideal starting point for reaching an effecient balance: high intensity excercise to increase metabolic effeciency paired with meditation excercise to reduce standing heart rate/stress hormones.
This has been my primary (ignored) hesitation with the consumption of coffee and other caffeinated beverages - the worry about the increased heart rate therefrom reducing my longevity. The threat has definitely not stopped my consumption, though maybe it has decreased it. A little.
Do you have any reason at all to believe that this is a meaningful effect, or an effect at all? Have you considered that gearing your life-long behavior towards adding seconds to your lifespan is, perhaps, the wrong tact?
If we very boldly assume these relationships are causal and predictive to individuals, it follows lower energy consumption -> longer life. Caloric restriction might be one way to do this.
However, with lower metabolism, stuff in the body tend to get older. This will make them fail more easily, then you are likely to get sick, which will shorten your life. Therefore the optimal strategy to maximum life expectancy seems to be control metabolism (by exercise / calory intake etc.) to a certain point where you are just unlikely to get sick, then stop.
[0] biology.stackexchange.com/questions/20489/is-there-any-relationship-between-heartbeat-rate-and-life-span-of-an-animalH