I pulled out 14A Low-carb “stone age” diet: PALEO because the word simply means old.

paleo-

before vowels pale- word-forming element used in scientific combinations (mostly since c. 1870) meaning “ancient, early, prehistoric, primitive, fossil,” from Latinized form of Greek palaios “old, ancient,” from palai “long ago, far back” (from PIE root *kwel- (2) “far” in space or time).

From the Online Etymology Dictionary

I used to joke that I’m on the real paleo diet: I eat whatever I have in the fridge, and I almost never go shopping. Also I eat in the dark.

But now I’m married, so that would reflect poorly on my wife if I were to continue to make that joke.

Theme!

20A First and only female prime minister of India: INDIRAGANDHI.
32A “Red Cube” sculptor with an eponymous museum in New York: ISAMUNOGUCHI.

42A First M.L.B. player to enter the Meikyukai (a Japanese baseball hall of fame): ICHIROSUZUKI.

57A Fashion designer and judge on “Project Runway All Stars”: ISAACMIZRAHI.

65D With 70- and 71-Across, agree … and a phonetic hint to this puzzle’s theme: SEE EYE TOEYE. The answers start and end with the letter I.

Finished this one in 15:34.

Day	This Wk	Best	Average	4-Wk Avg	Streak
Monday	4:41	3:49	9:23	5:15	78
Tuesday	9:11	5:22	13:13	9:53	2
Wednesday	15:34	7:38	17:03	15:57	19
Thursday		12:12	28:38	30:32	4
Friday		10:29	31:21	19:42	18
Saturday		20:12	33:30	32:27	18
Sunday		15:11	53:28	43:22	5