Blood ketone levels, body weight, heart, liver, and muscle mass after 2 months of a KD. (a) 3‐h postprandial and 12‐h fasted blood β‐hydroxybutyrate levels in middle‐aged female fed a control (CD) or ketogenic diet (KD). (b) Body weight, (c) percent fat measured using NMR relaxometry, (d) rearing score: Number of wall‐contact rears. Total distance travelled in (e) Y maze, (f) elevated plus maze, and (g) open field. Percent time spent (h) in center region of the open field and (i) on the open arms of the elevated plus maze. (j) Grip strength test: Relative to body weight. (k) Grid wire hang: Maximum hanging impulse. (l) Rotarod: Maximum time on the rod. (m) Time spent in the target quadrant and (n) latency to find the target hole in the banes maze probe trial. (o) Percent alternation in the Y maze spontaneous alternation test. (p) Percent time exploring the novel object in the novel object recognition time. Of female mice fed an isocaloric CD or KD. *indicates p < 0.05, **p < 0.01. All values are presented as mean ± SEM (n = 16).