that is high in fat
can be called "a heart attack
on a plate".
The phrase was used most famously, and perhaps first, by Michael Jacobson, the executive director of the watchdog group Center for Science in the Public Interest. Jacobson called fettuccine alfredo "a heart attack on a plate", and the phrase stuck.
Other candidates include the Big Mac, the Bloomin' Onion, and similarly fat-laden 'food'.