If meat is your main course, choose it broiled or baked rather than fried. The same advice applies to fish and potatoes, choose broiled or baked rather than fried. Don't smother foods with sauce or gravy. Sauces are usually high in fat. Drink plenty of fruit juices.
Natural juices are very low in fat, and high in carbohydrates.
At the salad bar, choose all the vegetables that you want, go light on the fried sidebar items and salad dressings. Also, be wary of items that are mixed with mayonnaise or other fat laden condiments. Eat plenty of bread and rolls, but without butter. For dessert, eat ice milk rather than ice cream. Both contain carbohydrates, but the fat content of the ice milk is lower than ice cream.