View source for Caloric Restriction

[[File:Food level, fecundity and longevity.jpg|thumb|Food level, fecundity and longevity. Median life span and fecundity are negatively affected by a very low nutrient concentration in higher eukaryotes. However, life span but not fecundity is optimized by dietary restriction (DR).{{pmid|20395504}}]]
'''Caloric restriction''' '''(CR)''', also known as '''calorie restriction''' or '''dietary restriction (DR)''', refers to a diet that reduces the intake of chemically bound energy from foods by 10 to 50 percent compared to ''ad libitum'' ("at will") nutrition. The goal is to achieve a higher life expectancy or at least delayed aging or health-promoting effects{{pmid|21663754}}{{pmid|19104499}}, without leading to malnutrition.

In a number of [[Model Organisms|model organisms]], a health-promoting and life-extending effect has been demonstrated through this method. However, no extension of life expectancy has been observed in some species or breeds. The extension of life expectancy in some rodent strains by up to 50%{{pmid|21840335}} is dependent on the genome and sex among other factors{{pmid|25269675}}.