You'll also want people to RSVP so you have a head count for the caterer. If, on the other hand, your rehearsal dinner will be fairly low-key or small (think: a party at a restaurant or an intimate gathering at your future in-laws' home) then you don't need to be as official with your invitations.
The exact nutritional value of an orange depends on its variety. According to the U.S. Department of Agriculture, a standard-sized navel orange contains 69 calories, 17.6 grams of carbohydrates and 11.9 grams of sugar.
In a Navel Oranges ( (1 Medium Orange Serving) ) there are about 69 calories out of which 2 calories come from fat. The total fat content of (1 Medium Orange Serving) Navel Oranges is 0.21 g. Within the fat content, a Navel Oranges contains 0.02 g of saturated fat, 0 g of trans fat, 0.04 g of polyunsaturated fat and 0.04 g of monounsaturated fat.