Pathway link CR-LONGEVITY

Fasting / caloric restriction Longevity

Fasting / caloric restriction activates Longevity.

Eating less improved health and survival in monkeys. But in mice that could eat as much as they wanted, cutting calories by watering down the food did not make them live longer; eating less protein compared with carbohydrate did. So whether it is the calories or the protein that counts is still open.

Caloric restriction improved health and survival in rhesus monkeys (MAT2017). In mice fed one of 25 diets ad libitum, lowering calories by diluting the food did not extend lifespan, while a lower protein-to-carbohydrate ratio did (SOL2014). That study is carried as conflicting evidence on which variable matters: calories, or protein.

The conditions it holds under

No human lifespan data exists. Effect direction is reproducible across several species; effect size and even the responsible variable (calories versus composition) are not settled.

Time it takes: long exposure (days to weeks)
Step: indirect (through steps not drawn here)
Measured in: rhesus, mouse
Reaches people?: not tested in people
How settled: emerging, few independent studies

Studies behind it

Year	Evidence	Study
2017	A	Caloric restriction improves health and survival of rhesus monkeysMAT2017 Direct comparison of two long-term primate CR studies (NIA, Wisconsin) supports consistent health benefits; the survival effect depended on study design and control-diet composition.

Points the other way

Year	Evidence	Study
2014	A	The ratio of macronutrients, not caloric intake, dictates cardiometabolic health, aging, and longevity in ad libitum-fed miceSOL2014 Lifespan and cardiometabolic health were determined not by caloric intake but by the protein:carbohydrate ratio; a low protein ratio was associated with lower hepatic mTOR activation.

Why the studies disagree

Opposing result. A study in a comparable system found the opposite direction or no effect. Another experiment would decide it. In mice fed 25 diets ad libitum, calorie restriction achieved by dietary dilution or by high-protein diets had no beneficial effect on lifespan; lifespan followed the protein-to-carbohydrate ratio (SOL2014).

Who has checked this

Checked by: No researcher outside the project has checked this link yet.
Curator sign-off: Not signed off yet. This link was drafted with AI help and has not been reviewed link by link; treat it as a proposal until it is.
Curated by: Oliver Barton, with AI help for drafting; see how links are checked.

“How settled” describes how far researchers in the field agree. It is not the same as the sign-off above, which only says whether a named curator has checked this page.

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Fasting / caloric restriction → Longevity