You could refer to something like a giant hamburger covered in cream cheese and bacon as 'scale-busting' .This suggests that if you ate it you'd get so fat that you'd break the scales the next time you tried to weigh yourself!

It usually means something so heavy it could break (bust) the scales. Extremely heavy, or heavier than the scales could measure. "Scales" as in "weighing device".

Can you give a full sentence and context, please? That will help us to give you a better explanation.