Why are you on a DIET?
The Big Bang Theory Season 7, Episode 2
that she decided
to go on a DIET...
The Big Bang Theory Season 7, Episode 12
"Wil, do you want more Diet Coke?
The Big Bang Theory Season 8, Episode 20
Diet Coke.
The Big Bang Theory Season 1, Episode 13
How hard is 65% Coke,
35% Diet Coke?
The Big Bang Theory Season 12, Episode 23