Con artist Sylvia Svelte
Sylvia Svelte (June Foray; 1917-2017) is the main antagonist from "Taste Makes Waist," a fifth season episode of Garfield and Friends (airdate October 3, 1992). She is the self-proclaimed "Queen of Cuisine," and she appeared on an infomercial promoting her diet food products, which caught the attention of Garfield, Jon, and Odie.
The trio rushed to Sylvia's Diet Center and bought her seven-day sample pack, which was highly expensive. Nevertheless, Jon (under Sylvia's coercion) purchases the food, and after they drive off, Sylvia secretly sends one of her employees to order her pizza and chili fries. To the trio's dismay, the diet food is not only in small portions, it tastes terrible (even Garfield dislikes it). When Jon returns to Sylvia and demands a refund, Sylvia has them thrown out.
Later on, Garfield sneaks onto the set of Sylvia's latest show, with pizza, Chinese food, and layer cakes (among other foods) in his possession. He later sets the food down and turns on the air conditioner on full blast, causing the aroma to reach Sylvia. The villainous host is taken by the aroma and develops an appetite, but not for her diet food, which she kicks away and exposes as junk. She later gobbles a pizza (which Garfield dangles in front of her) and demands a cheesburger and Chinese food.
Grateful to Garfield for the food, Sylvia promises to refund not only Jon, but everyone else who bought her bad diet food. The episode ends with Sylvia and Garfield dining together.