Table 1. Sample size per dietary group per experiment.

Figure	Ad libitum chow-fed rats	TRF standard diet-fed rats	TRF ketogenic diet-fed rats
Figure 1: Feeding pattern detection	Young n = 6 Aged n = 5	Young n = 7 Aged n = 5	Young n = 7 Aged n = 4
Figure 2: Keto-adaptation rate		Young n = 5 Aged n = 4	Young n = 5 Aged n = 4
Figure 3-4: Age-related metabolic impairment	Young n = 6-27 Aged n = 5-24
Figure 5: Insulin during keto-adaptation		Young n = 20 Aged n = 20	Young n = 20 Aged n = 20
Figure 6: Insulin tolerance testing	Young n = 6 Aged n = 5	Young n = 7 Aged n = 7	Young n = 7 Aged n = 6
Figure 7: Naïve vs experienced keto-adaptation		Young n = 10; Aged n = 8 All rats alternated dietary regiments, see text and Figure 7 for details.
Figure 8: Glycogen content in liver and muscle during keto-adaptation		Young n = 20 Aged n = 20	Young n = 20 Aged n = 20
Figure 9: Epinephrine-induced stress response		Young n = 6 Aged n = 8	Young n = 6 Aged n = 7
Figure 10A: Systemic glucagon		Young n = 4 Aged n = 4	Young n = 5 Aged n = 4
Figure 10B, 10C: Epinephrine-induced stress response in advanced age	Young n = 6 Aged n = 10 Advanced Age n = 5
Supplementary Figure 1: Glucose tolerance testing	Young n = 6 Aged n = 5	Young n = 7 Aged n = 7	Young n = 7 Aged n = 6