Jon has brought in a scale, and Garfield decides to tamper with it so he can trick Jon into thinking he is overweight.
Jon comes home and Garfield thinks his arrival will be on the news that night. He announces what he has bought; a new scale, which also tells fortunes. Garfield tests it, with the scale misunderstanding what he was trying to do. He is told that he is twenty pounds overweight; he is then hit with a "splut" pie, as per his fortune. Garfield then decides to tamper with the scale to trick Jon. Jon then tries out the scale, which tells him that he is fifty pounds overweight. With his fortune being that he will go on a strict diet, Jon decides to do just that.
Jon asks Garfield to keep him from eating too much. Garfield's solution is to give Jon a lettuce leaf, with Garfield getting a large amount of food placed on the table (this soon changes to Jon getting half a leaf). Afterward, Jon declares that he will do a workout, with a reluctant Garfield joining him. They get ready with a song before heading outside.
Jon and Garfield start by jogging through the driveway. Garfield quickly becomes tired, collapsing in front of the house. Jon suggests they go west, while Garfield suggests they go east. Jon thinks he just wants to take the shorter route; as he runs forward, he falls into an open manhole.
Later, Jon and Garfield try out some weights. Jon tries it alone, only to find it too hard. Giving a weight to Garfield, they each struggle to pull one of the weights. After spotting an apple on the ground, Garfield gives his weight back to Jon, who gets flung into the house. Garfield goes into the house to get an apple peeler; he finds Jon sticking out the kitchen wall and gets upset with him for taking a "break".
Jon and Garfield then dance to an aerobics workout record. Garfield is soon exhausted, prompting him to speed up the music to finish the workout sooner. The faster music causes Jon to move fast enough to fly. When Garfield stops the music, Jon falls down to the ground. Garfield advises him to stop.
Garfield returns to the scale, testing it before putting it back to accurate weight. The scale tells him he is still 20 pounds overweight, and that he will get more exercise. Jon then shows up to weigh himself again, with the scale telling him that he has the correct weight. His fortune is that he will punish Garfield for tampering with the scale before, revealing Garfield's ploy. In a rage, he chases Garfield out of the house and down the street, with the scale narrating each action. After mentioning that the duo "lived heavily ever after", the scale then announces "The End".
- The Scale (voiced by Julie Payne)
- The scale tells Garfield "You are twenty pounds overweight or nine inches undertall", likely a reference to Garfield's line "I'm not overweight. I'm undertall".