It's not just a sign of the holiday season. Food servings have been getting supersized everywhere, from restaurants to grocery shelves.

So it can be hard to know what a recommended portion size actually looks like anymore. Whether it's a scoop of ice cream or a serving of vegetables, it's probably a lot more than you think.

However, everyday items as well as your own hand can serve as visual guides.

For a one-cup measure of foods like cereal, fruit chunks or vegetables, picture a baseball, tennis ball or your own clenched fist. For a half-cup, picture that baseball cut in half or the front part of your fist.

Other common portion sizes may be even smaller than you realize. For instance, one tablespoon is about the size of your thumb tip. One teaspoon is the size of the tip of your index finger. And a teaspoon of a liquid, like olive oil, is the surface of a postage stamp.

Here's some holiday help for measuring other small amounts:

• One-and-a-half ounces of cheese is about the size of a 9-volt battery.
• A one-ounce piece of bread is the size of a 3" by 5" index card.
• One ounce of nuts should fit snuggly within the cup of your hand.

Three ounces of meat should fit into the flat square of your palm -- it's about the size of a deck of cards or a mini pack of facial tissues.

Get familiar with standard portion sizes by measuring everything you eat for at least one week using measuring cups and spoons, and a food scale. It's a great way to get in touch with the amounts you're consuming and just how oversized our idea of portions has become.