Esimating Size of Food Servings

The USDA's Nutrient Data Laboratory has created a table call Tips for Estimating Amount of Food Consumed in their publication "Nutritive Value of Foods"

" This table lists some handy tips to help you estimate the amount of food you eat when you cannot measure or weigh it."

Here is the table data:

Breads and grains
1⁄2 cup cooked cereal, pasta, rice: volume of cupcake wrapper or half a baseball
4-oz bagel (large): diameter of a compact disc (CD) medium piece of cornbread medium bar of soap

Fruits and vegetables
medium apple, orange, peach: tennis ball
1⁄4 cup dried fruit: golf ball or scant handful for average adult
1⁄2 cup fruit or vegetable: half a baseball
1 cup broccoli: light bulb
medium potato: computer mouse
1 cup raw leafy greens: baseball or fist of average adult
1⁄2 cup: 6 asparagus spears, 7 or 8 baby carrots or carrot sticks, or a medium ear of corn

Meat, fish, and poultry, cooked
1 oz: about 3 tbsp meat or poultry
2 oz: small chicken drumstick or thigh
3 oz: average deck of cards, palm of average adult’s hand, half of a whole, small chicken breast, medium pork chop

Cheese
1 oz hard cheese: average person’s thumb, 2 dominoes, 4 dice

Other
2 tbsp peanut butter: Ping-Pong ball
1⁄3 cup nuts: level handful for average adult
1⁄2 cup: half a baseball or base of computer mouse
1 cup: tennis ball or fist of average adult

Source: Susan E. Gebhardt and Robin G. Thomas, "Nutritive Value of Foods", USDA Agricultural Research Service, Home and Garden Bulletin, Number 72, rev. October 2002