Is there any way you can ask what will be served? Would eating before you go be an option? That might help reduce the temptation at least
At my husband's friend wedding they served hors d'oeuvres that I could eat like mushroom caps with cheese, dates wrapped in bacon (yeah I love dates I know they are sugary), and all sorts of little treats. Then the meal was great cuz you could make your own, so while people were grabbing rolls and eggs rolls and stuff, I loaded up on cheese, salad, and meat
And eh, a glass or three of wine