COBBERDOGS have a luxurious coat, so it isn't easy to tell by sight what is hiding beneath it.  Is it muscle, fat, or just bones?  Weigh them?  Well we all know that fat weighs less than muscle and that too fat isn't healthy either.
Just to complicate things more, two dogs can be the same height, weigh the same, and yet one can be too fat while the other is too thin.

The Easy Solution?  Learn to tell from feel.
There are key areas on your dog which you can feel to find out if your dog is a healthy weight.

*  you shouldn't be able to feel the bony knobs along the dog's backbone.  But if it feels broad and chubby the dog is too fat
*  pin bones are two bony points, one each side of the top of croup.  You should not be able to feel them.
*  Thighs should not be concave as in the picture.  You should feel a bulge which is flesh cover or muscle.
*  It's Okay to feel the ribs a little, but not the hollows between each one.
*  You should feel firm flesh on the shoulders, and not sharp bony points.

The belly is not an indicator. This dog's belly is round and fat (could indicate worms).

But notice the bony knobs along his spine, and his prominent pin bones.  Thighs are also flat with no fleshy or muscle cover.  These areas can be felt with your hands even if not seen underneath a long or thick coat.