Caloric restriction
Overview
Caloric restriction (CR), also known as calorie restriction, is a dietary regimen that reduces calorie intake without incurring malnutrition or a reduction in essential nutrients. It is a topic of interest in the field of gerontology due to its potential effects on health and longevity.
History
The concept of caloric restriction dates back to the 1930s, when researchers Clive McCay and Mary Crowell of Cornell University discovered that rats subjected to a diet with reduced calories, yet nutritionally balanced, lived significantly longer than rats fed a normal diet. This finding sparked interest in the potential benefits of caloric restriction in humans.
Mechanisms
The exact mechanisms by which caloric restriction exerts its effects are not fully understood. However, several theories have been proposed. These include the free-radical theory, the hormesis theory, and the protein metabolism theory.
Health Effects
Numerous studies have suggested that caloric restriction may have several health benefits. These include improved cardiovascular health, reduced risk of cancer, improved insulin sensitivity, and potential extension of lifespan.
Caloric Restriction in Humans
While the benefits of caloric restriction have been well-documented in animal models, its effects in humans are less clear. However, preliminary evidence suggests that caloric restriction may have similar health benefits in humans.
Caloric Restriction vs. Fasting
Caloric restriction should not be confused with fasting. While both involve a reduction in food intake, they differ in duration and intensity. Fasting typically involves abstaining from food for a set period, while caloric restriction involves a sustained reduction in daily calorie intake.
Criticisms and Controversies
Despite the potential benefits, caloric restriction has been criticized for its potential negative effects, such as nutrient deficiencies and reduced quality of life. Moreover, the long-term effects of caloric restriction in humans remain largely unknown.