The greedy reptile had been tucking into five piglets a month, which could have given her heart problems or diabetes, just like a human.
In desperation Ellie's owners handed the python over to Flambards Theme Park in Cornwall to sort out.
No crash diets for snakes
Flambards told The Sun newspaper that Ellie had been snacking on four times as much food as she needed.
Her new handler Mark Wiles has warned it could be a while before Ellie is back to her slinky self and it could take months before anyone notices a difference.