High fat content is the real culprit. We had a senior dog that survived 2 strains of Leptospirosis at the same time. (she had the 4-way vaccine on board) The Vet advised to start her on a low carb, high protein diet which was also high fat, (It was a well know higher end dog food) she survived the Lepto, it was the pancreatitis that did her in. Vets normally give out warnings with the Holidays because so many dogs end up with gastric upset or worse pancreatitis which is not always survivable.