5. "Let's go get ice cream."

Variations: "This celebration calls for dessert." "Just this once. . . ."

Why it's unhelpful: Tempting the person with foods you know she's trying to steer clear of is the opposite of offering support, nutrition expert Reardon says, even if you mean it as a harmless suggestion and even if it's for a "good excuse."

Better: Make an activity, rather than a food, the focus of a social outing or celebration. Propose a toast. Buy a gift (one that's not related to food). Invite your friend or loved one out for coffee or for a bike ride. Say, "Let's meet at the dog park" or, "Let's go have tea."