An introduction to calorie restriction at h+ Magazine: "In the early twentieth century nutrition researchers found that rats maintained on reduced caloric intake showed lower spontaneous tumors compared to rats fed ad libitum (allowed to eat as much as they chose). Although this work did not address caloric restriction (CR) and aging, it suggested that CR might slow the onset of age-associated disease in rodents. ... Numerous follow-up studies demonstrated that a micronutrient adequate CR diet significantly increased the lifespan of many species, largely crossing species boundaries. ... While CR increases the lifespans of most species examined, it also suppresses many of the diseases associated with human aging, thus increasing the 'health-span.' Over short periods, CR lowers blood pressure, heart rate, and glucose levels, and improves memory in older individuals and measures of cognitive performance in animals. Over longer periods CR significantly reduces the risk for many different types of cancer, age-related brain atrophy, heart disease (and atherosclerosis related diseases), autoimmune disease, and adult onset diabetes. CR appears to lessen the risk for, and attenuates or even reverses the symptoms of Alzheimer's and possibly Parkinson's diseases; two major age-related neurodegenerative diseases that cause enormous human suffering. ... Interestingly, CR appears to promote the progression of Amyotrophic Lateral Sclerosis (Lou Gehrig's disease), indicating it does not protect from all human diseases. Aging causes extensive, often organ-specific changes in gene expression patterns. Analysis [has] shown that aging, calorically restricted mice show gene expression patterns resembling those of young animals, compared to ad libitum-fed mice of the same age. CR also lowers cellular oxidative damage by reducing mitochondrial oxygen free radical production, lessens age-related telomere shortening, lowers inflammation, increases DNA damage repair efficiency and lowers damage to DNA and RNA (thus promoting genomic stability), lowers insulin levels while promoting insulin sensitivity, reduces the number of senescent (non-dividing) cells that accumulate with aging, attenuates age-related cellular protein cross-linking, and increases the removal of damaged cellular proteins - a process called 'autophagy' which declines with age and plays a role in resistance to infection, cancer, heart disease, and neurodegeneration. "