The ingredients tell the story here. Eggnog’s creaminess comes from whole eggs, whole milk and cream. One mug will deliver about 400 calories and 22 grams of fat. The classic chocolate martini, made with creme de cocoa, chocolate liqueur and vodka, also rings in at around 400 calories but has considerably less fat. But former bartender and registered dietitian Tina Ruggiero warns that some specialty chocolate martinis include heavy cream, so ask first before you order.