During Michael's first visit to Deidre, he removes his short sleeve shirt from over top of his sleeveless t-shirt. It's alternately on and then off again in the next several cuts.
The license plates used in "Toledo, OH" are clearly the thinner yellow Australian plates, not the red white and blue Ohio plates.
When the camera is angled at Deidre's crotch, you can clearly see that the "fat suit" is build up from separate segments.
Near the end of the film when Philip and Michael are getting on and off Deidre's bed which is attached to a scale the needle never moves from Deidre's 602lb weight.
If you look very carefully at the opening police scene, supposed to be in Hamburg, Germany, you can catch a glance of one of the police vans in front of the house. There one can see that this vehicle has right-hand-steering.