Helping your pet dog lose weight by playing games like fetch. It’s easiest to teach them outside, so your dog’s chase drive will be high. If your pet is uninterested in retrieving a ball or runs off with it, make a slit in a tennis ball and show your dog that you’re dropping some treats inside. Toss the ball and excitedly encourage them to get it. They will be interested in getting that ball filled with treats. When you get the ball back, squeeze it to make the treat drop out and let them eat the treats. This should encourage your pet to play fetch and, in the process, stay active.