His DIET is rich in fatty deli meats.
The Big Bang Theory Season 6, Episode 9
This thing has to hold up
against a hearty potato-based DIET.
The Big Bang Theory Season 2, Episode 22
Why are you on a DIET?
The Big Bang Theory Season 7, Episode 2
"Wil, do you want more Diet Coke?
The Big Bang Theory Season 8, Episode 20
Wrong. She just took a sip
from his Diet Dr. Pepper.
The Big Bang Theory Season 6, Episode 2