How to Convert Food Serving Sizes to Grams
While some people find dieting success through journaling, attending support meetings or simply keeping junk food out of the house, others require a more structured strategy, such as measuring and weighing out specific serving sizes. While it might be a bit overwhelming to begin the process, it becomes relatively simple once you’re used to the numbers. For foods that clearly indicate a serving size on the nutritional label, all you’ll need is a calculator and basic math skills. For fresher foods or those without a nutritional label, a food scale will surely become your favorite gadget.
Using a Calculator
Identify the serving size noted on the nutritional label. Most packaged foods clearly indicate the amount of food included in one serving; the nutritional information provided on the label is for that exact serving size. Depending on the food, the serving size might be given in cups, ounces, teaspoons or tablespoons.
Convert ounces to grams by using the conversion factor of 1 ounce to 28 grams. Multiply the number of ounces in one serving size by the number 28.
Convert cups to grams with one extra step. First, convert cups to ounces. Because there are 8 ounces in 1 cup, divide the number of cups in one serving size by the number 8 -- this will give you the number of ounces in the serving size. Then, multiply that number by 28 to get the number of grams.
Perform an extra step when converting tablespoons and teaspoons to grams, as well. First, convert the measurement to ounces -- there are 2 tablespoons in 1 ounce and 6 teaspoons in 1 ounce. So, if your serving size is 4 tablespoons, divide this number by 2 -- so you have 2 ounces. Similarly, if your serving size is 3 teaspoons, divide that number by 6 -- so you have 0.5 ounce. Continue with the conversion by multiplying the number of ounces by 28 to achieve the number of grams.
Using a Scale
Position a food scale on a flat, level surface. Make sure it's set to measure in grams -- rather than ounces -- and turn the scale on.
Zero the scale if you’ll be using a bowl, plate or dish to hold the food you’re weighing. To zero the scale, put the empty dish on the scale and press the “zero” button on a digital scale or turn the knob on a spring or weight scale until the needle reaches zero.
Deposit one serving size of the food you’re measuring onto the scale. Wait for a few seconds as the scale registers the weight.
Read the weight displayed on the scale; this is the total weight in grams of the food.
Things You Will Need
Krista Sheehan is a registered nurse and professional writer. She works in a neonatal intensive care unit (NICU) and her previous nursing experience includes geriatrics, pulmonary disorders and home health care. Her professional writing works focus mainly on the subjects of physical health, fitness, nutrition and positive lifestyle changes.