You might want to consider having your vet check your dogs thyroid level. My boxer did this and was also overwieght... He is now on daily thyroid medication and a much tighter diet... His nose is almost back to normal, his weight is much better, he barely snores anymore and has much much more energy again. Oh and one of the ladies that works for the vet said that her dog did the same and the problem was Cushings. So either way it might be a good idea to ask your vet.