Weddings are a wonderful occasion to celebrate and enjoy some fabulous food and drink so I'm not suggesting you skip the cake and champagne altogether but some advance planning can help keep your blood sugar and waistline in check!
Firstly have a good breakfast as wedding breakfasts can be served pretty late. Go for low GI carbs such as muesli, porridge or wholemeal or rye bread combined with low-fat protein such as natural yoghurt, eggs, trimmed bacon, tofu or whey protein. This will help keep hunger at bay, regulate blood sugar levels and the low GI carbs are also good for calming nerves if you're in the wedding party.
Pack some healthy snack bars in your jacket pocket or purse, I like wallaby or laar bars (fruitus if you're not gluten free). These are easy to eat discreetly before the wedding or on your way from the church to the reception to keep hunger at bay and energy levels up.
Try and avoid drinking alcohol on an empty stomach, this will spare you feeling hideous the next day and reduce the risk of over-indulging when the food is served. If champagne is served before canapes then take a few small sips to be polite and enjoy the champers properly once you've had at least a few nibbles. Any high fat low-carb canapes such as cheese or parma ham will help slow stomach emptying keeping you full til the main meal is served and slowing the absorption of alcohol into your bloodstream. During the meal and speaches try and alternate your glasses of water with wine to pace your intake and avoid an early headache.
If you are really commited to watching your weight and don't want to over-indulge the best strategy is to keep the event low carb, so enjoy cheese, smoked salmon and hams for appetizers and the meat, fish and non-starchy veg in your starter and main course but avoid any potatoes, rice or bread and skip the cake in favour of the cheese board. This will also help keep you fuller for longer reducing the desire for late night munchies.
If this all falls by the wayside and you find yourself a bottle of champagne down and halfway through your third slice of cake don't give yourself a hard-time - weddings are an occasion to celebrate so enjoy the party and get back on the health wagon the next day.