lol my Molly is on a permenant diet---because she inherited my metabolism 

try giving other types of treats, like baby organic carrots ($3/HUGE packet), bell peppers, or green beans boiled in homemade chicken or beef broth (low sodium). This way, he'll still get yummy treats, but he'll be on a diet... Also lean cuts of meat cubes are good snacks
Sometimes I'll spread a little laughing cow light cheese on Molly's bell pepper slice and she goes crazy for it. 
    
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 Chrissy, Izze (Yorkshire Terrier),Molly & Suzie (Toy Poodles), Chachi (Chihuahua)