My Cairn Terrier is very overweight so we started only feeding him a cup of food a day (split into two portions - one in the morning & one at dinner time- recommended by the vet) and taking him for lots of walks and runs. We recently took him to the vet and he told us to continue to walk him & keep his activity level up (he likes to just lay around a lot). There is another problem though, he vomits a lot... Could all of this be a sign of a thyroid problem? Vet said to take him back in 3 months and if he hasn't lost any weight then that may be the case..but I wanted to get other opinions. I'd say he vomits atleast every other day..sometimes it's his food & other times it's just grass. I am very worried & concerned because our last Cairn fell victim to cancer, so of course all these bad things have been running through my mind.. :\ Should I just wait it out and see if we can get him to lose the weight?