“no matter how you look at the issue, prevention is a fundamentally preferable and more cost-effective way to promote health and longevity. On an individual level, am I more likely to eat unhealthy foods and exercise insufficiently if I know I’ll have access to medical care to treat the symptoms of the diseases these choices cause many years later? More broadly within our society, is the money we allocate to treating diseases coming at the expense of money to prevent them?” It is worthwhile to ask to what extent efforts to treat the symptoms of common mismatch diseases have the effect of promoting dysevolution by taking attention and resources away from prevention. Prevention really is the most powerful medicine, but we as a species consistently lack the political or psychological will to act preventively in our own best interests. “study of thirty thousand elderly people in fifty-two countries found that switching to an overall healthy lifestyle-eating a diet rich in fruits and vegetables, not smoking, exercising moderately, and not drinking too much alcohol-lowered heart disease rates by approximately 50 percent.14 Reducing exposure to carcinogens, such as tobacco and sodium nitrite, have been shown to decrease the incidence of lung and stomach cancers, and it is likely (more evidence is needed) that lowering exposures to other known carcinogens, such as benzene and formaldehyde, will reduce the incidence of other cancers. Whatever selection is operating is probably occurring at a pace too slow to measure in our lifetimes.” Every year new products and therapies are being developed that allow people with common mismatch diseases to cope better with their symptoms.
Some obesity-related illnesses can hinder reproductive function, but these problems have strong environmental causes.9 Finally, although culture sometimes spurs selection, it is also a powerful buffer.
Type 2 diabetes, for example, generally develops after people have reproduced, and even then, it is highly manageable for many years.8 Another consideration is that natural selection can act only on variations that affect reproductive success and that are also genetically passed from parent to offspring. One reason is that many of these diseases have little to no effect on fertility. “Human evolution is not over, but the chances of natural selection adapting our species in dramatic, major ways to common non-infectious mismatch diseases are remote unless conditions change dramatically. ― quote from The Story of the Human Body: Evolution, Health, and Disease
The term epidemiologists coined for this phenomenon is the “extension of morbidity.” In addition, many of the other leading causes of death today are chronic illnesses such as asthma, Alzheimer’s, type 2 diabetes, and kidney disease, and there has been an upsurge in the occurrence of nonfatal but chronic illnesses such as osteoarthritis, gout, dementia, and hearing loss.63 Altogether, the growing prevalence of chronic illness among middle-aged and elderly individuals is contributing to a health-care crisis because the children born during the post–World War II baby boom are now entering old age, and an unprecedented percentage of them are suffering from lingering, disabling, and costly diseases. Many cancer patients also remain alive for several years following their diagnosis because of chemo-therapy, radiation, surgery, and other treatments. Some heart attack victims die within minutes or hours, but most elderly people with heart disease survive for years while coping with complications such as high blood pressure, congestive heart failure, general weakness, and peripheral vascular disease. In contrast, the two most common causes of death in 2007 America were heart disease and cancer (each accounted for about 25 percent of total deaths). The two most common causes of death in 1935 America were respiratory diseases (pneumonia and influenza) and infectious diarrhea, both of which kill rapidly. The downside is that he or she also should expect to die more slowly. Roosevelt signed the Social Security Act in 1935, old age was defined as sixty-five years, yet estimated life expectancy in the United States at the time was sixty-one years for males and sixty-four years for females.62 A senior citizen today, however, can expect to live eighteen to twenty years longer.