This one doesn't need an explanation right?
But let's do it
Joke:
“I’m on a seafood diet! I see food, and I eat it.”
Why it’s funny:
At first, “seafood diet” sounds like a diet where someone only eats seafood (fish, shrimp, etc.).
But then the sentence continues and breaks the expectation:
“sea food” sounds like "see food" (food that you see)
So the “diet” is actually: Whenever I see food, I eat it.
The humor comes from:
Wordplay (same sound, different meaning)
The contrast between a healthy-sounding diet and a very unhealthy habit