For many people, one of the toughest challenges when planning a party is trying to decide how much food they will need to serve. I'd love to say that there is a fool-proof formula to solve this dilemma but, in the end, the answer to this question involves more art than science.
Many factors come into play when you make your plans including the length of your party, the type of food you'll be serving, the composition of men, women and children in your group, as well as the richness of the food you plan to serve. The time of your party is also very important. An after-dinner cocktail party requires much less food than an all-afternoon barbecue.
Fortunately, there are a number of general principles you can follow when planning your menu and recipes. Begin by following these "rules of thumb" and write down your initial thoughts. Then look at the big picture several times over a period of a few days to make adjustments to your plan.
Always round up your estimates, don't round them down.
Anticipate which food selections will be most popular and serve more of them than the general portion guidelines suggest. For example, shellfish appetizers are always popular, so serve as much as your budget allows.
The more choices you offer, the smaller your calculation of individual portion size should be.
That said, you can assume your guests will taste everything on a buffet, but the tastes will be small. However, overall consumption per individual will be greater than if there were fewer choices.
Add "bulk" items to your menu. For a sit-down dinner have plenty of bread to fill in any hungry spots. When hosting a cocktail party, nuts, olives, pretzels, etc. provide a little extra security that you'll have enough for all but requires no extra work.
Here are basic guidelines for individual serving sizes of various foods. Multiply these estimates by your number of guests and, once again, always round up your estimates.
PORTION SIZE PER PERSON
6 bites when preceeding a meal.
4 - 6 bites per hour when hors d'oeuvres are the meal.
The longer your party and the larger your guest list, the greater the number of selections you should offer.
The Main Meal
Poultry, meat or fish - 6 ounces when you have one main dish, 8 ounces when you offer two or more main courses.
Rice, grains - 1.5 ounces as a side dish, 2 ounces in a main dish such as risotto.
Potatoes - 5 ounces
Vegetables - 4 ounces
Beans - 2 ounces as a side dish
Pasta - 2 ounces for a side dish, 3 ounces for a first course, 4 ounces for a main dish
Green Salad - 1 ounce undressed weight
1 slice cake, tart or pastry
4 ounces creamy dessert such as pudding or mousse
5 ounces ice cream
When serving two of the above, reduce each by a little less than half.
A FEW OTHER MENU PLANNING TIPS
Don't repeat a main ingredient. For example, don't serve a shrimp appetizer and shrimp main dish.
Consider the colors of the food that will be served together and make sure there is variety.
Offer both hot and cold foods on a buffet.
Mix textures such as a crisp potato galette served with a soft vegetable puree as side dishes.