[sliverstorm]

I still haven't really figured out how CR is supposed to be sustainable. I am around BMI of 19, and have been as low as 17 (6'2", 133lb). I become extremely unhealthy when I don't eat enough. As far as I know, I can't eat less and maintain the same weight. CR would, for me, send me to the hospital. Is CR just another name for "lose weight"? Is it working towards a goal rather than a lifelong steady state of living?

[cheeko1234]

Caloric restriction is an experimental tool that utilizes “undernutrition without malnutrition.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4115619/

A simple interpretation of CR would be: “additional leanness from a normal body weight may add health and life span delaying the process of aging.”

Regarding BMI, rule of thumb is 20-ish.

CR in the NIA study reduces body weight by 25%, so the NIA CR “man equivalent” will have a BMI of 20.8 (in the lower half of the normal weight category)

[sliverstorm]

Ok, so really it's just about targeting a leaner body composition, that makes a lot more sense. Thank you.

[joe_the_user]

I have the same body type. I've read about people doing CR who go from average body type to something like your or my body type (I was once 6' 135lb but I've gotten up to 150lbs lately).

As the OP say, there's very little basis to CR given you're talking mostly animals that are overeating and under exercising by default.

And mice are genetically uniform. CR has been partly tested on monkeys and other animals but it's a lot harder and results less conclusive.