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Part: 6 Picture Perfect > Term Paper #2 - Pg. 347

Sample Term Papers 347 Walford found that for the best results to achieve the longest life extension in his mice with the fewest negative side effects, calories should be restricted by 30 percent of what would be taken freely by the mice, and essential nutrients must still be consumed (Mlot 162). Dietary reduction of other things, such as fat intake, may be beneficial to health, but it does nothing to extend life span (Whitlock). Mice usually live anywhere from 38 to 40 months. When calories were restricted by 30 percent, they lived from 56 to 57 months, which is roughly equivalent to 147 years old in human terms ( Man Immortal). Among his findings, Walford discovered that the mice lived about 30 percent longer than average, weighed about 30 percent less than usual, had lower blood pressure, lower levels of serum cho- lesterol, lower concentrations of circulating glucose, lower triglyceride concentrations, lower insulin levels, and greater insulin sensitivity. In short, their bodies were becoming extremely efficient at utilizing the few calories that were put into it (Weindruch 49). The animals had stronger immune systems, and the onset of common late-life diseases, such as certain cancers, were held off as well (Weindruch 48). Why It Works Walford knew that reducing calories was slowing metabolism in the mice and improving their health in general, but he was unaware of exactly what was causing the slowing of the metabolism, and why it caused the extension of life span in the mice. In order to explain what was triggering the results, we first look at worms. Nematodes have an average life span of 14 days. However, at times when food is scarce, such as when overpopulation occurs, the seemingly simple worms have the ability to switch into a state of suspended animation known as the Dauer phase, "dauer" being the German word for "durable," during which they can live for two months or more, which is over four times longer than usual. Scientists such as Cynthia Kenyon at the University of California at San Francisco are studying the