Table 13.- — Maximum age of rats before weight loss in relation to caloric intake during the first 300 days 



on SP 8 HVO and SPE diets 





Rats 



Average 

 healthy 

 lifespan 



Intake during — 



Diet and age of 

 rats (days) 



0-12 weeks 



100-199 days 



200-299 days 





Average 



Range 



Average 



Range 



Average 



Range 



SP8HV0: 



Less than 500 _ 

 500 to 599 . 



Number 



15 



12 



11 



6 



20 



11 



6 



Days 



387 

 541 

 624 

 757 



330 

 423 

 533 



Calories 



6, 110 

 6,000 

 5,870 

 5,590 



6, 180 

 6,330 

 5,610 



Calories 



5, 260-6, 860 

 5, 220-6, 960 



4, 840-6, 720 



5, 030-5, 920 



5, 540-7, 120 

 5, 690-6, 820 

 5, 020-6, 340 



Calories 



8, 320 

 8, 170 

 7,760 

 7,890 



8,260 

 7, 940 

 6,830 



Calories 



7, 190- 9, 780 

 7, 280-10, 060 

 6, 160- 8, 930 

 6, 670- 8, 410 



6, 760-10, 180 

 6, 170- 9, 140 

 5, 500- 8, 100 



Calories 



8,510 



8,220 

 7, 900 

 7,450 



8,610 

 8,210 

 6, 950 



Calories 



7, 100- 9, 870 

 7, 280- 9, 780 



600 to 699 _ 



6, 530- 9, 020 



700 and over 



SPE: 



Less than 400. _ 

 400 to 499... .. .. 



6, 720- 7, 990 



7, 060- 9, 290 

 6, 690-10, 180 



500 and over. 



5, 570- 7, 730 



DIET: SP 8 HVO 



DIET: SPE 



GRAMS" 

 800 



.A' 



v. A' 



„A-A- 



- 







- 



- 





^-^ 



- 



- 



/ .& 

 J, A 

 V ' 



/ ' A ' 



- 



j 



If 





— 



_A 





-o Obese rats 







(423 days*) 



— 





A- 



-a Long-lived 







1 



rats (623 day 



1 



s* 



Obese rats 

 (553 days*) ~ 

 a— a Long-lived 



rats (812 days* 



I I I U 



150 300 450 600 150 300 450 600 

 DAYS DAYS 



* AVERAGE ACE AT DEATH 



Figure 6. — Comparison of growth curves of obese rats 

 fed SP 8 HVO and SPE diets with those of long-lived 

 rats fed the same diets. 



diets are all for rats weighing 600 grams or more 

 by 200 days. Of the 18 rapidly growing rats fed 

 these three diets, 8 were dead before reaching 

 400 days of age; only 1 survived 600 days (603 

 days on SPB diet). The rats that were still 

 maintaining their weight at 600 days of age grew 

 slowly on all three diets and survived approxi- 

 mately 300 days longer than did the rapidly growing 

 rats fed the corresponding diet. The slowly 

 growing rats tended to reach maximum weights 

 comparable to those attained by the rapidly 

 growing rats but at a much older age. 



No data were available from this study to 

 indicate the possible advantage of restricting food 



721-631—64- 



intake to prevent the excessive weight gain of the 

 older rats fed these diets. The tendency for rats 

 to become heavy at an early age when fed SPM 

 and SPPB diets may be a factor in the relatively 

 large number of early deaths on these diets. Al- 

 though a rapid gain in weight was generally asso- 

 ciated with a short lifespan, a slow rate of early 

 gain did not necessarily result in a long, healthy 

 life. 



The results with other experimental diets show 

 a similar trend for rapid early growth to be 

 associated with early death, but are too few to 

 permit their separation as has been done for the 

 diets just discussed. The tendency to a shortened 



27 



