. -A' .A' .A A oâ-o Obese rats (456 days*) a--a Long-lived rats (737 days*) â OâO / A'A- / X p A'A~A â / A' ~ / ^ " ? A' / ^' / / / / 1' it 11 II 1 O- O -A Obese rats (382 days*) AâA Long-lived rats (682 days*) 1 1 1 1 0 150 300 450 DAYS 0 150 300 450 DAYS ^AVERAGE ACE AT DEATH 0 150 300 450 600 DAYS Figure 1 .â âComparison of growth curves of obese rats fed SPM, SPB, and SPPB diets with those of long-lived rats fed the same diets. survival period for rats fed lard (SP 8 lard and SP 16 lard) may be due in whole or in part to excessive consumption, along with the tendency to more efficient
. -A' .A' .A A oâ-o Obese rats (456 days*) a--a Long-lived rats (737 days*) â OâO / A'A- / X p A'A~A â / A' ~ / ^ " ? A' / ^' / / / / 1' it 11 II 1 O- O -A Obese rats (382 days*) AâA Long-lived rats (682 days*) 1 1 1 1 0 150 300 450 DAYS 0 150 300 450 DAYS ^AVERAGE ACE AT DEATH 0 150 300 450 600 DAYS Figure 1 .â âComparison of growth curves of obese rats fed SPM, SPB, and SPPB diets with those of long-lived rats fed the same diets. survival period for rats fed lard (SP 8 lard and SP 16 lard) may be due in whole or in part to excessive consumption, along with the tendency to more efficient utilization of these diets. Discussion^âThere have been extensive inves- tigations on the nutritional requirements of the rat, but the majority of them have dealt with the period of early growth. Relatively few have covered the entire lifespan. Many of the early experiments concerned with longevity have dealt with diets deficient in one or more nutrients, result- ing in retarded growth and in premature death. Although growth has been the basis for studying nutritional adequacy of many diets, considerable evidence has accumulated to indicate that rapid growth in early life may not insure optimum health throughout life. McCay {120) was the first to demonstrate that lifespan of rats could be extended by severely restricting caloric intake while maintaining adequate levels of essential protein, minerals, and vitamins. With much less restricted intakes (33 and 46 percent) and without severe retardation of growth and sexual maturity, Berg and Simms (21, 22) showed an extension of life expectancy and a delay in the onset of major diseases. Ross (166, 28 167), investigating the effect of uniform lifelong dietary regimens on the mortality pattern of rats, demonstrated the possibility of modifying life expectancy not only by quantitative dietary restriction but also by the ratio of the protein and carbohydrate components in the diet. Riesen, Herbst, Walliker, and Elvehjem (158)
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Keywords: ., bookcentury1900, bookpubli, booksubjectdiet, booksubjectnutrition
