Should I give my dog human food?

Since winning promotion in my job at Goldman Sachs in January I have sadly found I haven't had enough time to devote to exercising and feeding my dog Rufus. The exercising isn't such a problem as Rufus is a lazy dog and he often likes to stay in the car when we are 'out and about' anyway. However, I have found now I am at home less rather than preparing seperate meals for myself and Rufus it's easier just to make two of whatever I am having. Rufus eats like a prince and wolfs it down. However all is not well. He has ballooned in size and become aggressive to people (a huge embarassment to me). Is his diet to blame? Can I get round it by giving him smaller portions and cutting out stuff like chocolate and ice cream?