To calculate portion sizes, use your hand as a simple guide to gauge the proper portion size for your body and weight. If your intention is to streamline your portions, use slightly less than the hand-oriented measurement.
Fitness enthusiasts and doctors, for example, refer to hand size as a source of proper portion size. Sometimes called the handful diet, it suggests that your portions should not exceed what you can hold in your hand, fit in your palm or anything larger than your fist.
A single serving of fruits or vegetables should be roughly the size of your fist. Meat, fish or poultry should be approximately the size of a deck of cards or the size of your palm, minus the fingers. A portion of pasta should be about the same size as a scoop of ice cream.
For slightly active male adults, the breakdown includes two handfuls of protein, roughly two handfuls of carbohydrates and one handful of green vegetables at every meal. For active women, the portions are one handful of protein, one handful of carbohydrates and one handful of green vegetables at every meal. Both sexes should eat one to two handfuls of fruit daily and one to two scant handfuls of healthy, monounsaturated fats.
When eating out, ask for smaller portions or eat half of the total amount served. At home try to avoid seconds.