The history of dieting is filled with trends and trendsetters and two notables recently died.  The first is C. Joseph Genster, who helped mastermind the marketing of the first liquid diet beverage in the 1960s.  It began with a vanilla flavored powder you mixed with water, followed by a liquid milkshake called Metracal that came in vanilla, chocolate and butterscotch, followed by cookies, clam chowder, tuna and noodles.  The idea was to limit daily calories to 900 total calories; each can...